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Congress Scientific ReportEAO 25th Annual Scientific MeetingParis, 29 September – 1 October 2016

Issue 2, February 2017

ContentsAcknowledgements � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 4Methodology � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 4Copyright � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 4

Decision-making on the basis of the level of disease: conservation versus extraction � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 5Periodontal therapy or implant therapy? How do we judge when to select one or the other? � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 5Deciding between conservation or extraction of periodontally compromised teeth with a questionable prognosis � � � � � � � � � � � � � � � � � � � � � � � 6

Soft and hard tissue grafting: prevention and management of complications � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 7Prevention and management of soft tissue defects around implants � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 7GBR in vertical and horizontal defects: how to reduce complications � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 9How to reduce complications using autogenous bone blocks � � � � � � � � 10

A digital revolution � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 12Virtual smile design to drive the restorative plan � � � � � � � � � � � � � � � � � � � � � � � � � � 123D engineering in contemporary implant dentistry � � � � � � � � � � � � � � � � � � � � � � � 13Optical impression and implant reconstruction: where are we? � � � � � � 15

40,000 implants down the road: What did we learn? � � � � � � � � � � � � � � � � � � �16Some thoughts on ailing and failing implants � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 1640,000 implants down the road: what did we learn? � � � � � � � � � � � � � � � � � � � � � 18

Contest by the Junior Committee: ‘7 minutes to convince’ � � � � � � � � � � � 21An original concept to present new research in implant dentistry � � � 21Digital working in implantology (parts 1 and 2) � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 21The conometric concept to make fixed implant-supported restorations � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �22A customised solution for 3D defects � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �23Effective implant surface decontamination during peri-implantitis treatment: what is the secret? � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �24Point of view perspective of a dental implant patient � � � � � � � � � � � � � � � � � � � �24Voids and areas of reduced mineralisation in healed sinus grafts: a prospective study using immediate and 6 months’ cone beam computerised tomography � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �25Results � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �25

Treatment planning session: a clinical case with a ‘complex’ problem or involving extensive rehabilitation � � � � � � � � � � � � � � � � � � � � � � � � � � � � 26Case presentation � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �26The clinical decision-making process for extraction and implant placement � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �27Clinical decision-making process � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �29Case completion � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �30

Festival of complications � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 31Treatment planning away from biological and technical complications � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 31Removable implant reconstructions: factors influencing incidence and type of complications � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �32How to solve – or better how to avoid – technical complications � � � �34

Bone biology: where do we stand? � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �35Cell biology and immune response related to implant dentistry � � � � �35Bone to implant interface: where do we stand and where do we go? � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �37What is osseointegration in 2016 and why are we losing bone around dental implants? � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �38

Tips and tricks for a successful implant practice � � � � � � � � � � � � � � � � � � � � � � � 40Introduction to the EAO Education Programme � � � � � � � � � � � � � � � � � � � � � � � � � � 40How photography can improve your private practice � � � � � � � � � � � � � � � � � � � �42Private practice management and development � � � � � � � � � � � � � � � � � � � � � � � � �43

How to avoid the carpenter’s approach to implants � � � � � � � � � � � � � � � � � � � �44The influence of insertion torque on primary stability, implant survival and marginal bone loss � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �44Evidence-based implant carpentry� What are you using, what are we doing? � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 46Bone versus implants! Do we need to grant the biomechanical to the biological? The orthopaedist’s perspective � � � � � � � � � � � � � � � � � � � � � � � �47

Emerging technologies: head-to-head � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 48Hand guided surgery versus guided surgery � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �48Autogenous bone blocks versus allogeneic bone blocks � � � � � � � � � � � � � 50Connective tissue graft versus soft tissue substitute around implants � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �52

Optimal long-term results for osseointegrated implants � � � � � � � � � � � � �53A new strategy for bone augmentation � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �53An analysis of dental implant treatment based on biomechanics and mechanobiology � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �54

Implantology needs periodontology � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 56Periodontal plastic surgery to prevent biological complications in the aesthetic zone � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 56Bone management for optimal aesthetic outcomes � � � � � � � � � � � � � � � � � � � � 58

Things we stopped in our practice due to failures � � � � � � � � � � � � � � � � � � � � � 60Immediate implant placement � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 60Prosthodontic rehabilitation of edentulous jaws � � � � � � � � � � � � � � � � � � � � � � � � � � �62Immediate CAD/CAM restoration � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �63Cement-retained restorations � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � �64

Debate: ‘machined or rough implants?’ � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 66Machined vs� rough implants: 30 years of experience � � � � � � � � � � � � � � � � � � 66Clinical advantages of modern micro-rough implant surfaces � � � � � � � �67

Please give me back my smile! Decision-making in the aesthetic zone: challenge your speakers� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 68How to manage complex cases in the anterior maxilla using a multidisciplinary approach � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 68Contemporary management of complex aesthetic dilemmas with an interdisciplinary approach � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � 70

Congress Scientific ReportEAO 25th Annual Scientific MeetingParis, 29 September – 1 October 2016

This report provides a summary of 16 principal sessions which took place at the EAO’s 25th annual Scientific Meeting. The report was written by a group of delegates at the meeting who have previously prepared similar summaries for circulation among their friends following past EAO meetings.

As described in the methodology, all speakers were given the opportunity to review and amend the editorial that had been written about their presentation, although a significant minority did not respond to the editors’ requests for feedback. The EAO wishes to emphasise that this is not a peer-reviewed scientific report. It was written by the team of volunteer delegates, albeit with input from a large number of the speakers represented. The contents do not necessarily represent the view of the EAO and readers are responsible for independently evaluating any information contained in the report. Nonetheless, the EAO hopes that the report will provide a useful and informative summary of the proceedings of its 25th annual Scientific Meeting.

Congress Scientific Report, Issue 2, February 20174

Acknowledgements

The EAO would like to gratefully acknowledge the substantial work carried out by Lino Esteve and Alberto Salgado in writing this report. They were supported by David Esteve, Guillem Esteve, Javier Amigo, Juan Navarro, Sandra Ferri, Tatiana Fernández, Alfonso Díaz, Vicente Belvis and Andrés Valdés.

Methodology

The methodology underpinning this report is as follows:

1. A team of dentist delegates volunteered to write the report and arranged to attend all the sessions covered in it during the EAO’s 2016 meeting in Paris

2. They provided a draft summary of each presentation to the EAO, which arranged for a copywriting team to edit it. This was not a scientific editing process, and instead concentrated on grammar and consistency

3. The editors returned the edited contributions to the dentist delegates highlighting any questions they had4. On receipt of responses to their questions, the editors updated the contributions, then forwarded them to

each of the speakers featured, along with a request for a selection of their slides (selected by the writers)5. Each speaker was emailed up to three times to request their feedback. The majority replied and supplied

slides. Some speakers provided textual corrections but declined to provide copies of their slides6. A small number of speakers did not respond to any of the emails sent to them, and as a result the editorial

on their sessions has not been reviewed by them

Copyright

A number of speakers allowed a selection of their slides to be included in this report. Readers should be aware that copyright in any original content included in these slides remains the property of the speakers, and/or any other third-party copyright holders. These slides must not be circulated other than as part of this report, and should not be copied or reused without the express permission of the relevant speakers.

Congress Scientific Report, Issue 2, February 2017 5

Decision-making on the basis of the level of disease: conservation versus extraction

Making the choice between conserving or extracting teeth is an everyday dilemma. Furthermore, the increasing popularity and reliability of dental implants means that implant-supported prostheses are often now considered comparable or even superior to natural dentition.

But this view is starting to change. High rates of long-term complications associated with implants are being reported, along with different inflammatory responses observed around implants compared with around natural teeth. As a result, the scales should tip back in favour of preservation of teeth. In this session, everyday decision-making processes were outlined from a strictly periodontal point of view.

Periodontal therapy or implant therapy? How do we judge when to select one or the other?Giano Ricci

Is it worthwhile trying to save natural dentition in advanced periodontal cases? The speaker asserted that he is in favour of saving natural teeth, and only uses implant therapy when the prognosis of the tooth is hopeless.

It has been possible to predictably treat a variety of periodontal defects for almost 50 years. Techniques and materials have changed, but predictability remains dependent on the regenerative potential of the defect (Figure 1.1.1).

Natural teeth require the same conditions as dental implants to remain healthy: they must be stable;

contained within an envelope of bone; and free from bacteria (Figure 1.1.2).

Based on his extensive clinical experience, the speaker outlined the SVI rule. He described the three conditions which make it worthwhile to perform regenerative periodontal therapy on a tooth1:

� stability � vitality � intactness

If the tooth does not meet these conditions, a dental implant should be considered.

1 Ricci et al. Int J Periodont Rest Dent 2011

Figure 1.1.1 Figure 1.1. 2

Congress Scientifi c Report, Issue 2, February 20176

Deciding between conservation or extraction of periodontally compromised teeth with a questionable prognosisGiovanni E. Salvi

Prognosis and treatment predictabilitySome teeth can be treated predictably, and their prognosis is secure. Others have a hopeless prognosis and have to be extracted. In the middle of the spectrum are teeth with a questionable prognosis, and these were the focus of the presentation (Figure 1.2.1).

Periodontal intrabony defects can be successfully and predictably treated for up to 30 years2. Basic periodontal treatment can transform a prognosis from initially doubtful to favourable. Depending on the case, these teeth may even be used as abutments for conventional prosthetic restorations.

Periodontal therapy should aim to eliminate pockets exceeding 6mm in order to avoid the progression of periodontal disease and tooth loss3 (Figure 1.2.2). Tooth loss in periodontal patients can be reduced signifi cantly if good plaque control is maintained4 (Figure 1.2.3).

2 Cortellini & Tonetti. J Clin Periodontol 2004; Pini Prato & Cortellini. J Clin Periodontol 2016

3 Matuliene et al. J Clin Periodontol 20084 Axelsson et al. J Clin Periodontol 2004

Teeth have higher survival rates than implants and lose less supporting bone over time. A 10-year follow-up clinical study has demonstrated that this is true for periodontally compromised patients, whether they are smokers or not5.

The risk of implant loss in patients who are treated for chronic periodontal disease is 1.59 times higher than in healthy patients. In cases involving aggressive periodontitis, patients are up to 4 times more likely to experience implant loss6. It has been demonstrated that a suboptimal treatment of periodontitis is related to a higher risk of peri-implantitis7.

Conclusions � wherever possible, the emphasis should be on

preserving the natural dentition � periodontal therapy should be successfully

completed before implant treatment begins � enrolment in regular supportive therapy should

be encouraged � periodontally treated teeth can be used as

abutments for prosthetic restorations

5 Rasperini et al. J Periodontol 20146 Sgolastra et al. COIR 20157 Pjetursson et al. COIR 2012

Giovanni|Salvi Mrs. J. L., 1975

Surgical periodontal therapy 34-36

Figure 1.2.2

Giovanni|Salvi

Extraction

Irrational to treatQuestionable

Wikipedia: Prognosis (Greek: „fore-knowing, foreseeing“)

medical term for predicting the likely outcome of one’s current standing

Secure

2 years following periodontal regeneration

Figure 1.2.1

Giovanni|Salvi

Change in periodontal prognosis

Scaling & Root Planing alone!

July 2012 June 2015

Mr. K. M., 1947

Figure 1.2.3

Congress Scientifi c Report, Issue 2, February 2017 7

Soft and hard tissue grafting: prevention and management of complications

In this session speakers reviewed the prevention and management of complications in three tissue augmentation treatments: soft tissue grafting, guided bone regeneration and autogenous bone blocks.

Prevention and management of soft tissue defects around implantsJacques Malet

A treatment plan should be developed in reverse, working from the desired fi nal outcome back to the initial situation. The prosthesis should be designed before an implant is placed, and an optimal position must be located before the implant is inserted. In the same way, the amount of soft tissue and bone volume required for a successful outcome should be calculated before surgical steps are taken. Unfortunately, however, most treatment plans do not include this diagnostic phase. This increases the likelihood of clinical problems arising after treatment, such as marginal tissue recession (Figure 2.1.1).

It is well-known that papilla levels depend mainly on the levels of interproximal bone at the adjacent tooth. Facial marginal mucosal levels, however, are affected by several other factors, including interproximal bone

levels, peri-implant biotype, facial bone level, implant fi xture angle, depth of implant platform, and level of fi rst bone-to-implant contact1.

What are the causes of soft tissue complications?Bone remodelling:

Soft tissue complications can arise as a consequence of bone remodelling, and usually become apparent some time after the implant has been placed. In one study, complications were measured in a series of 11 maxillary anterior implants and the average values were as follows:

� buccal bone height: 0.7 –1.3mm � buccal bone thickness: 0.4 mm � facial soft tissue margin: 0.7mm2

1 Nisapakultorn et al. COIR 20102 Cardaropoli et al. COIR 2006

m e n u

i n t ro d u c t i o n

e t i o l o g y

t r e a t m e n t

p r e v e n t i o n

c o n c l u s i o n

Figure 2.1.1 Figure 2.1.2

Figure 2.1.4Figure 2.1.3


GBR:

There is little data concerning the long-term success and stability of hard and soft tissues around implants following GBR procedures. It is thought that GBR does not completely prevent reduction of bone volume . Currently, only a few studies have assessed the stability of the augmented buccal bone, and a recent systematic review has concluded that soft tissues in these studies were not adequately measured3.

Immediate implantation:

Acceptable aesthetic outcomes may be achieved with immediate implant placement (Type 1). Recession of the mid-facial mucosa is an aesthetic risk in cases involving Type 1 placement – higher than in early or delayed implant placement (Types 2 or 3) – and especially in cases with thin-tissue biotypes or socket wall defects.

Recessions measuring more than 1mm were present at 1–3 years in 9–41% of Type 1 implant sites. Additionally, two retrospective studies using CBCT detected no buccal wall in 36% and 57% of the sites. Recession continued during a 2–8-year follow-up period. The effect of gingival biotype on peri-implant tissue response seemed to be limited only to facial gingival recession, and did not influence interproximal papilla or proximal marginal bone levels4.

How can we treat and prevent these complications?The gold standard in preventing complications continues to be the connective tissue graft, which can achieve a mean defect coverage of 66%, 96% and 89.6%5 (Figures 2.1.2–4).

3 Ludtz et al. COIR 20154 Chen & Buser. IJOMI 2014; Kan et al. IJOMI 20115 Burkhardt et al. COIR 2008; Zuchelli et al. COIR 2013;

Roccuzzo et al. COIR 2014, respectively

Using this well-known technique, four steps must be followed:

� the surface must be thoroughly decontaminated � maximum blood supply must be preserved � the donor site must be carefully selected � surgical trauma must be minimised

Outcomes tend to be stable over time but implant surface coverage is unpredictable, especially where the position of the implant is non-ideal. The current focus is on limiting patient morbidity, but the risk of a poor outcome is reduced when a stepped procedure following the above guidelines is performed over time.

In a cross-sectional study looking at 24 immediately placed implants, 14 were re-evaluated using CBCT at a 7-year follow-up visit. Five of those evaluated showed no buccal bone over the implant surfaces. They presented a mucosal margin 1mm more apical in comparison to implants with intact buccal bone. No correlation was found between initial bone volume defects and bone dimensions at the 7-year follow-up.

Prevention of complicationsComplication prevention is based on achieving an ideal balance between bone and soft tissue.

Prevention using GBR: early placement of implants (Type 2 or 3), combined with simultaneous GBR, is a proven protocol in the prevention of further defects, as GBR encourages soft tissue generation.

Prevention using immediate implantation: case selection is crucial. Thin biotypes should be avoided, and tissue volume should be overbuilt. In cases featuring thin biotypes soft tissue regeneration using GBR is recommended, along with a preventative connective tissue graft.

Residual defects should be corrected with connective tissue grafts.

Figure 2.1.5

implant coverage failure proximal bone support implant decontamination ?3D implant positionning

Figure 2.1.6


GBR in vertical and horizontal defects: how to reduce complicationsJaime Lozada

Membrane exposure is the main complication that is reported in GBR procedures. It has the potential to signifi cantly jeopardise the fi nal result. Where membrane exposure occurs, the graft can become infected and the amount of augmentation fi nally achieved is seven times lower than in undisturbed sites. The literature shows a great variability in the incidence of this complication, ranging from 7 –80%. In 3–15% of cases the graft became infected, and in 50% regrafting was required. Early membrane or graft exposure is often due to fl aps that are poorly designed or too small, which in turn are responsible for poor clinical outcomes.

The speaker described his early experiences of GBR, when he was working alongside Dr Philip Boyne. At that time, GBR was performed with a titanium mesh and a mixture of autogenous intraorally harvested bone graft and bovine bone-derived biomaterial. At six months, the procedure resulted in 36.47% new bone formation, and 15.11% volume resorption6.

The speaker also discussed a more recent collaboration with Dr Istvan Urban, where the technique was performed with titanium-reinforced dense-PTFE membranes and a combination of particulated autogenous bone and anorganic bovine bone-derived mineral (ABBM). In a prospective case series of 25 patients, histomorphometric measurements of the augmented tissue revealed that 31.0% was comprised of autogenous bone, 25.8% of ABBM and 43.2% was occupied by marrow space7. In a recent long-term evaluation of the technique the mean vertical bone gain was 5.1 ±1.8mm, and was 7.0 ±1.5mm horizontally. No intraoperative or postoperative complications were noted 1–15 years after loading8.

6 Proussaefs & Lozada. J Oral Implantol 20067 Urban et al. Int J Periodontal Rest Dent 20138 Urban et al. Clin Implant Dent Rel Res 2016

As a result of this collaboration, a classifi cation of fl ap designs has been proposed when performing vertical ridge augmentation in the atrophic anterior maxilla. The four clinical conditions proposed under this classifi cation are:

1. Shallow vestibule with healthy periosteum 2. Deep vestibule with healthy periosteum3. Shallow vestibule with scarred periosteum4. Deep vestibule with scarred periosteum

The aim of this classifi cation is to allow clinicians to achieve tension-free closure and more predictable vertical bone gain9 (Figures 2.2.1–4).

The speaker identifi ed several guidelines that should be taken into account in order to reduce complications in GBR:

� ample surgical access � tension-free fl ap � site preparation, graft selection and fi xation � membrane selection and fi xation � connective tissue graft � primary closure � post-operative care

He also outlined the following key factors on which the success of the techniques is based:

� preventing the soft tissues collapsing into the defect

� stabilising the particulate bone graft � protecting the surgical site against blood clots and

osteogenic cells � excluding competing non-osteogenic cells and

resorptive factors � suturing technique (double layer sutures) � surgical dexterity

9 Urban et al. Int J Periodontal Rest Dent 2016

Type IDeep Vestibule

Remote Flap + Periosteal Incision + Separation of Elastic Fibers +

Double Layer Suture

Figure 2.2.1

Type IIShallow Vestibule

Safety Flap + Papilla Shift Technique + Subobicularis

Preparation + Double Layer Suture

Figure 2.2.2


How to reduce complications using autogenous bone blocksMatteo Chiapasco

As clinicians, we are often faced with defects which may require bone reconstruction, such as:

� 3D defects in the aesthetic area (especially in high smile lines)

� atrophic posterior ridges in both jaws, where there is not enough room for short or even ultra-short implants

� extreme atrophy of the mandible, where there is risk of mandibular fracture

� severe atrophy of the maxilla, with no possibility of placing short or tilted implants

Several techniques have been described to reconstruct alveolar ridge width and height to resolve these issues. Autogenous bone blocks are one of the most successful techniques, and are widely considered to be the ‘gold standard’.

Are procedures using autogenous bone blocks successful?There is evidence that autogenous bone blocks can be successfully used to augment horizontal defects using a two-stage approach. Using this technique, according to a recent systematic review, one study reported that a linear bone gain of 4.3mm can be expected at the time of implant placement, with a mean initial ridge width of 3.2mm. In cases involving vertical ridge augmentation, bone blocks produced a mean linear bone gain of 4.7mm when at least 4mm of vertical augmentation is needed.

The main complications associated with bone blocks are: wound dehiscence and graft exposure; infection and sequestration, or non-integration and even total loss of the graft; and late bone resorption. The mean complication rate is 6.3% in horizontal ridge augmentation (mainly graft exposure), but a high complication rate can be expected in vertical augmentation (graft exposure in 12.5–33.33% of cases; graft loss in 8–20%; mean complication rate of 8.1%)10.

Six tips and tricks to prevent complications (Figures 2.3.1–6)1. Ensure there is adequate blood supply to the graft2. Ensure adequate modelling and fi xation of

the block3. Cover the bone block with slowly

resorbable xenografts4. Make releasing incisions for a tension-free fl ap5. Do not load or compress the reconstructed area

with removable provisionals6. Wait for integration of the graft, and never place

immediate implants

ConclusionDue to morbidity, bone grafts should be limited to cases where less invasive procedures are not suffi cient. It must also be remembered that a 100% success rate is unlikely, as there are risks involved in any surgical procedure. Reported complication rates vary greatly. Should the proven protocols be strictly followed, however, these rates can be limited.

10 Milinkovic & Cordaro. IJOMSurg 2014

Type IIIDeep Vestibule

Remote Flap + Periosteal Incision with Periosteoplasty + Separation

of Elastic Fibers + Double Layer Suture

Figure 2.2.3

Type IVShallow Vestibule

Safety Flap + Periosteal Incisions with Periosteoplasty + Papilla Shift

Technique or Periosteal Excision + Separation of Elastic Fibers + Double

Layer SutureFigure 2.2.4

RULE # 1- Adequate blood supply to grafts Multiple cortical bone perforations to improve re-vascularization of the graft

RULE # 2 Adequate periosteal releasing incisions to obtain a tension-free suture of the ßaps


RULE #1 – Adequate blood supply to graftsMultiple cortical bone perforations to improve re-vascularization of the graft

RULE #2Adequate periosteal releasing incisions to obtain a tension-free suture of the � aps


RULE # 3 Adequate Þxation of the graft with close contact with recipient site

RULE # 4 Fill any residual gap between graft and recipient site and Fill any residual gap between graft and recipient site and cover the bone block with autogenous bone particles mixed cover the bone block with autogenous bone particles mixed with slowly resorbable xenografts

RULE # 5 Stabilization of graft particles with resorbable Stabilization of graft particles with resorbable membranes and water-tight and tension-free suture of membranes and water-tight and tension-free suture of the ßaps over the reconstructed area

RULE # 6 No load/compression by removable prostheses on the reconstructed area No load/compression by removable prostheses on the reconstructed area for at least 4-6 weeks after the surgery for at least 4-6 weeks after the surgery Maryland bridges, vacuform retainers, Þxed provisionals with no load on the Maryland bridges, vacuform retainers, Þxed provisionals with no load on the operated areas are OK. operated areas are OK. After 8 weeks, in particular in fully edentulous patients, removable After 8 weeks, in particular in fully edentulous patients, removable prostheses relined with soft materials are allowed

Figure 2.3.4

Figure 2.3.5

Figure 2.3.6

Figure 2.3.3

RULE #4Fill any residual gap between graft and recipient site and cover the bone block with autogenous bone particles mixed with slowly resorbable xenografts

RULE #5Stabilization of graft particles with resorbable membranes and water-tight and tension-free suture of the � aps over the reconstructed area

RULE #6No load/compression by removable prostheses on the reconstructed area for at least 4–6 weeks after the surgery

Maryland bridges, vacuform retainers, � xed provisionals with no load on the operated areas are OK

After 8 weeks, in particular in fully edentulous patients, removable prostheses relined with soft materials are allowed

RULE #3Adequate � xation of the graft with close contact with recipient site


A digital revolution From diagnosis to planning and execution, treatment processes are becoming increasingly digitalised. The ability to create and place prosthetic restorations on both natural teeth and implants using a completely digital workflow is now a reality. This is having a profound effect on daily practice, and its advantages cannot be ignored. During this session, the speakers mapped out and assessed how far we have come with digital implant dentistry.

Virtual smile design to drive the restorative planMarcelo Calamita

Predictability and communicationPredictability is crucial in implant treatment. In 90% of cases, achieving a sufficient level of predictability depends on an accurate diagnosis and a suitable treatment plan which takes into account aesthetics, function, biology and structure. Communication is vital both between the patient and the clinician, and among the treatment team. Digital workflows allow all aspects of communication to be enhanced.

Currently, the main digital diagnostic tools are: CBCT, CAD/CAM, iOS and DSD. These allow us to make diagnoses, develop treatment plans, present cases and manage treatment. This makes our workflow with patients, colleagues and technicians much more effective.

Case 1, using Digital Smile Design (DSD)When making up a treatment plan using DSD, the first step is to use a digital face-bow. The aim is to identify and relate facial landmarks – such as the glabella, philtrum and mentum – to reference planes, such as the eyebrows, interpupillary distance, or the interalar and intercommissural width. Once these have been identified, the facial/dental midline is marked, and the smile-line, interdental proportions and tooth outline can be determined. A digital ruler can help us configure the ideal parameters for this particular case.

One of the main benefits of using DSD is that the predicted final result, made using these calculations,

can be shown to the patient before the treatment is started. Digital planning allows the operator to easily discuss the pros and cons of the proposed treatment with the patient, and outline in advance any potential limitations or compromises that may be encountered.

The speaker then described a clinical case which involved a severe volume defect in the aesthetic zone. The treatment, which included placing two implants, began with orthodontic extrusion, intended to make the gingival margins level. Next, hard and soft tissue grafting was performed; finally, a hybrid fixed prosthesis was placed, along with a prosthetic gingival reconstruction.

Case 2This case involved a vestibular recession with an unaesthetic appearance caused by a poorly positioned implant at 11 which needed to be explanted. Following socket repair, three connective tissue grafts and extensive soft tissue conditioning, the case was completed using porcelain veneers and a single implant crown.

The speaker recommended that the initial treatment plan that is shown to the patient should be created in 2D. Once they have accepted the plan, the operator’s team and lab should be briefed. Only then can the plan progress and the clinician develop a solution in 3D, using either analogue or digital tools.


3D engineering in contemporary implant dentistryWael Att

Digital dentistry has three main stages (Figure 3.2.1):

� data acquisition (involving registration, charting, photos or video being taken, facial scanning, intraoral scanning, model scanning, and CBCT)

� planning/processing (data-merging, implant planning, computer-assisted design)

� fabrication/execution (CAM via subtractive or additive procedures, and treatment itself)

Bone imaging using CBCT alone is not enough to complete the diagnosis, because it cannot convey key information about soft tissue and prosthetics. To complement the CBCT scan, intraoral scans and/or model scans should be used. The images gathered can be superimposed by means of fi ducial markers to give more precise information about the relation between hard and soft tissues and the proposed prosthesis.

Data acquisition has two requirements: the prosthesis being used during acquisition has the ideal positions of the teeth; and fi ducial markers are located to allow the two images (from CBCT and iOS) to be merged. In cases where the existing prosthesis is not ideal, a template should be fabricated with the ideal position of teeth as a point of reference.

The template can be created using either an additive or subtractive process. The subtractive process is fast, stable and accurate, but is unable to make undercuts or complex structures. Once it has been verifi ed that the appliance fi ts, guided surgery can be performed reliably. The speaker cautioned that although it is a reliable procedure, it is limited by the fact that some deviation is inevitable during surgical navigation1.

Different intraoral scanners employ different methods of scanning, using either light or laser technology (Figure 3.2.2). It has been estimated that results can vary by approximately 70μm, but the level of imprecision may be higher in cases involving edentulism. Other factors to bear in mind when considering intraoral scanning are:

1 Van Assche et al. COIR 2012; Tahmaseb et al. IJOMI 2014

� the greater the number of implants, the lower the accuracy

� the use of landmarks is strongly recommended � mobile mucosa cannot be digitised2

The next step involves virtual registration and mounting. One method consists of scanning the articulator with the casts already mounted, but a mechanical face-bow must be used. Alternatively, using a ‘PlaneFinder’ device, reference points can be located quickly and the procedure can continue in a fully digital environment, without the need for mounting plaster casts on a mechanical articulator.

The next problem is how to merge the soft anatomical structures. Combining 2D and 3D data can be useful for gathering information about how the teeth appear from the front, but it is of little help in providing information about lateral orientation and position, and is not a useful patient communication tool. This step must therefore be done using facial scanners.

Facial scanners can be static (3D) or dynamic (4D). The main applications of static facial scanners lie in plastic surgery, orthodontics and orthognathic surgery, although they have limited applications in prosthodontics. Information gathered by these scanners can be combined with CT or CBCT fi les by being superimposed over them.

Dynamic facial scanners use continuous photo-capture with 50 frames per second, but cannot be combined with CT or CBCT scans, as the latter are static and therefore incompatible. 3D-over-3D superimposition has the potential to be a valuable technique, but requires further simplifi cation before it can be used in daily practice. CAM has multiple possibilities – one of the most interesting being the use of monolithic zirconia prostheses – although the lab technique to suitably mimic aspects of the tissue must fi rst be mastered (Figures 3.2.3 and 3.2.4).

2 Patzelt et al. JADA 2013; Patzeit et al. COIR 2015

3dPrinting

THE 3 COMPONENTS OF DIGITAL DENTISTRY

Model scan

Intraoral scan

CT/ CBCT

Face scan

Registration

Mounting

Charting

Photo VideoData

Acquisition

MillingGrinding

selective laser sintering

stereo-lithographydigital light processing

TXCAM

Additive

Subtractive

Fabrication/ execution

CAD

Implant PlaNning

Data merging

PROS PLANNING

planning/ processing

Figure 3.2.1


Conclusion � the more data and information that is acquired,

the more precise the rehabilitation will be � a completely digital approach is currently

unavailable for complex rehabilitations � a combination of conventional and digital

techniques can enhance communication and patient care

� a major drawback is that the team must be experienced and well-trained

� future technologies have the potential to streamline the workfl ow and accelerate the manufacturing process

INTRAORAL SCANNERS - TECHNOLOGY OVERVIEWLight Technology

Light + Sensor

Active Triangulation

with Strip Light Projection

Real Time Image CaptureStill-image Capture

Video Capture

Active Wavefront Sampling

Ultrafast Optical

Sectioning

Stream projection

• Lava COS • True Definition

• Trios • Bluescan-I

• CEREC Omnicam • CEREC BlueCam • APOLLO DI

• CS 3500

Amplified Light Technology

Laser + Sensor

Confocal Moiré-Projection

• iTero •E4d Dentist •PlanScan

Still-image capture

Laser Triangulation

•Zfx • i/s/can oral

Real Time Stitching

Parallel Confocal Laser Light Imaging

Figure 3.2.2

ColoringCAM

MONOLITHIC ZIRCONIA

Figure 3.2.3

FinalColoring

Figure 3.2.4


Optical impression and implant reconstruction: where are we?Nelson Silva

How far we are with digital dentistry?Throughout his presentation, the speaker emphasised that it is possible to perform many dental procedures supported by a range of digital tools that are currently available: the technology exists now. This extends to both restorative and non-restorative techniques.

Using CAD/CAM technology, we can obtain high resolution captures which can be used to develop the ideal design of fixed prostheses. This includes calculating margin location and adjustments, insertion axes and even the suitable colour and shade of the restored tooth. These CAD files can then be transferred to the CAM system to create prostheses rapidly and easily. The manufacturing process can use various materials and feature subtractive or additive processes. The speaker talked about how he was involved in an investigation to develop a new ceramic printing procedure3.

He described various cases involving partial fixed implant prostheses, outlining his planning process using CBCT, and illustrating how surgical guides can be digitally designed and fabricated using CAM, with two methods currently in use: milling or 3D printing. This technique allows for less invasive

3 Silva et al. J Prosthodont 2010

surgery and ensures that the implant is placed in the correct 3D position. He demonstrated how the CAM process can be utilised to allow increased precision, more detailed customisation of abutments and improved aesthetic outcomes.

He went on to describe various cases involving removable prostheses, and illustrated various steps of the treatment plan:

� use of the virtual articulator � laser sintering of the metal framework � CAM fabrication of a complete prosthesis

In aesthetic dentistry, digital tools such as intra- and extraoral photographs, intraoral scanners, and colour assessment tools can help clinicians perform better facial and dental analyses. This data can be used to design CAD-based restorations and create digital wax-ups. These can be used to evaluate the final outcome digitally before physically placing the prosthesis. If the patient is satisfied with the proposed solution, the treatment can be carried out.

The speaker also mentioned several promising non-restorative computer-assisted applications, which can monitor tissue recession, wearing or changes in volume with great precision.


40,000 implants down the road: What did we learn?

This session featured speakers from the Brånemark Clinic in Gothenburg, Sweden, and reviewed what they have learned over a period of 30 years, during which over 40,000 implants have been placed at the clinic. Their experience clearly demonstrates the effectiveness of dental implants, which have proved to be stable and predictable for the majority of patients over three decades. Nevertheless, failures and complications can and do occur. This session explored some of the causes behind these complications and failures.

Some thoughts on ailing and failing implantsBertil Friberg

Failures and complications: where can we fi nd the causes?Four potential sources of failures and complications can be identifi ed:

� components: the devices and materials used or the ‘hardware’

� technique: how treatment is carried out or the ‘software’

� performer: the clinician’s attitude, experience and skills

� patient: the recipient’s bone and systemic conditions

ComponentsSince moderately rough surfaces were introduced in 2003, the incidence of early implant failure has fallen from 2.5% to 1.5% in the mandible and from 9.3% to 1.8% in the maxilla. The use of tapered implant designs (like the Mk IV) allowed for increased primary stability, which is benefi cial when placing implants in soft bone or during immediate loading protocols1.

1 Friberg et al. Clin Implant Dent Rel Res 2003

Surgical techniqueThe use of longer and angulated implants has also improved outcomes2. In addition, for systems such as the standard Brånemark implant the fi nal drill diameter used in the osteotomy can be reduced, achieving higher insertion torque and implant stability quotient (ISQ) values, leading to increased primary stability. Failure rates are low among straightforward cases, but levels were found to be signifi cantly higher in more complex cases involving advanced surgical techniques (Figure 4.1.1).

Performer: surgeon competence and performanceA 28-year study of 11,074 procedures analysed the impact of the surgeon on the outcomes. Factors that can infl uence early implant failures were found to include:

� individual surgeons’ level of experience � surgeons’ attitude and self-confi dence � whether structured routines or clearly defi ned

protocols were in place � co-operation of the surgical team3

2 Friberg et al. IJOMI 19913 Jemt et al. Clin Implant Dent Rel Res 2016

Having failures, one may search for reasons amongst used techniques: Yes!with more advanced procedures

inlays

onlays

Immediate insertion;direct loading

Zygoma

Figure 4.1.1


Complex cases and poor support were also associated with higher stress levels, which led to higher rates of intraoperative complications and early failures.

PatientThere are three key stages at which patient-related factors can infl uence the likelihood of an implant failing:

� placement, resulting from poor bone quality and/or volume

� the establishment of osseointegration, resulting from non-optimal systemic conditions

� post-operative maintenance, such as the build-up of biofi lms due to poor dental hygiene

Poor bone volume and qualityA variety of treatment approaches have been suggested to address situations where there is insuffi cient native bone. These include augmentation using bone grafts or bone blocks, or the use of short implants. These procedures have more risks associated with them than conventional treatment (Figure 4.1.1).

Severe general and local osteoporosis has been identifi ed as a potential obstacle for osseointegration, especially in extreme conditions where jaws appear empty and have no visible internal bone structures on radiographic scans. Conversely, several studies have concluded that osteopenia did not contribute to implant failures4.

Nevertheless, clinical problems are not caused by poor bone volume or low bone density alone. A combination of the two is often what leads to complications. This is especially the case when immediate loading is involved (Figure 4.1.2).

Systemic bone disease and age at surgeryPatients with systemic diseases affecting mesodermal tissues (bone, cartilage, or connective tissue) can often benefi t from successful implant

4 Friberg et al. Clin Implant Dent Rel Res 2001; Holahan et al. IJOMI 2008

treatment. Such diseases include of X-linked hypophosphatemia; Langerhans cell histiocytosis; lupus; scleroderma; and osteogenesis imperfecta. Case reports with 15 years of follow-up have demonstrated good survival rates in such cases5.

Patient age alone is not an indicator of the likely success or failure of implant treatment. Tooth loss has been cited as an independent predictor of mortality in the population. Younger patients who have lost many or all of their teeth are therefore generally associated with a higher risk of systemic problems. Accordingly, a number of younger patients contributed to the overall number of total implant failures and bone loss after 5 years in the case series being discussed6.

Persistent bone-level biofi lmsMany early implant losses are due in part to overheating in dense bone caused by poor drilling technique or bone compression following insuffi cient preparation or self-tapping. Another possible cause seems to be the re-emergence of a latent infection, which may then spread rapidly around the implant and cause failure. In other cases, infection can lead to development of a fi stula, also known as apical peri-implantitis. Kassolis and colleagues found that such conditions may originate in regions of necrotic bone and consequent subclinical infection, leading to early implant failure7. They carried out a histopathologic study on 154 bone samples obtained during implant osteotomy preparations from both jaws. Regions of microbial biofi lm formation and non-viable bone were discovered after as little as one year following tooth extraction and mucosal healing. They concluded that these fi ndings may contribute to the development of osteonecrosis of the jaw and early implant failure. In post-extraction alveolar bone which had apparently healed, the persistence of bacterial biofi lm has also been discovered following microbiological analysis8 (Figure 4.1.3).

5 Friberg et al. Int J Periodontics Rest Dent 20136 Friberg & Jemt. Clin Implant Dent Rel Res 20157 Kassolis et al. Bone 20108 Nelson & Thomas Clin Implant Dent Rel Res 2010

Thus…...it is not poor bone volume per se!

..it is the combination of the two that implies problems!!

.. and especially so when handling immediate loading!!

..it is not the poor bone texture per se!!

mental foramen

Figure 4.1.2

• bone compression

• over-heating

• revival of latent infection (mainreason for earlylosses!!!!!)

Bone loss due to self-tapping implants/surgical technique?

Fistula

Figure 4.1.3


Maintenance of osseointegration: peri-implantitisThe diagnosis of peri-implantitis continues to be controversial. Bleeding on probing is not a reliable parameter for marginal bone loss. Probing pockets can be similarly unreliable, as the depth of the peri-implant sulcus may depend on a number of factors:

� implant position � abutment length � mucosal swelling9

A radiographic evaluation of bone level over time remains the most reliable tool for identifying implants undergoing continuous bone loss10.

At the sixth European workshop of the European Federation of Periodontology (EFP) in 2008, it was stated that there was limited evidence that the proposed surgical and non-surgical treatments could resolve a significant proportion of peri-implantitis lesions (28%–56%)11. A more recent clinical study

9 Coli et al. Periodontology 2000 201610 Coli et al. Periodontology 2000 201611 Lindhe & Meyle. J Clin Periodontol 2008

concluded that oral hygiene treatment and/or surgery to combat peri-implantitis did not reduce the implant failure rate or marginal bone loss recorded in the 88 treated patients, when compared with non-treated patients12.

Were success rates higher in the past?A clinical review currently being conducted highlights some circumstances which may explain the higher survival rates and lower complications registered in earlier decades (Figure 4.1.4). These can potentially be attributed to a variety of factors. Implants are now used for a much wider range of indications, and surgical procedures have become more advanced, pushing the boundaries of what is possible and in some cases increasing the level of risk. Additionally, some new components such as aesthetic abutments have been associated with higher levels of bone resorption. There is a trend towards more biological complications associated with more complex cases, and a correspondingly greater risk of failures.

12 Jemt et al. Clin Implant dent Rel Res 2015

40,000 implants down the road: what did we learn?Torsten Jemt

Effectiveness and efficacyThe speaker began by describing how data on 11,600 patients and 50,700 implants has been gathered from both the Brånemark Clinic in Gothenburg (relating to public dental care), and from a private referral clinic. The data covers the period when osseointegration was still a controversial topic, continuing right up to the present day. Rather than being based on prospective randomised studies that have been carried out under strict conditions, it reflects the effectiveness of implant treatment as delivered in routine general practice. He asserted that in his opinion the ‘real world’ nature of the data made it more relevant than data obtained from RCTs13.

Teeth vs. implants1-year survival rates are marginally better in cases involving restored teeth than those involving implants (Figure 4.2.1). However, predicting long-term outcomes based on short-term results – and assuming these results will remain linear – is

13 Rothwell PM. Lancet 2005

not a reliable procedure. The table in Figure 4.2.2 demonstrates that we can reasonably expect single implants to have a better long-term survival than restored teeth in routine practice (Figure 4.2.2).

Are we over-estimating peri-implantitis?In a 9-year follow-up study of 145 patients previously identified as having progressive bone loss and peri-implantitis14, the progressive bone loss previously reported could not be confirmed. Implants classed as both ‘affected’ and ‘unaffected’ exhibited the same mean bone loss during follow-up15. Moreover, initial bone loss cannot be considered a predictor for future bone loss or increased risk of implant failure.

This challenges the claim that all patients identified with peri-implantitis should undergo surgical treatment. The results of the above study indicated that patients who were treated showed slightly more bone loss at the 9-year follow-up than those who

14 Fransson et al. COIR 200815 Jemt et al. Clin Implant dent Rel Res 2015

Implants of the old days:• Mainly total edentulism, no implants in partial edentulism with

periodontally compromised situations• Period of edentulism prior to implant placement, healed bone without

signs of infections• Implants mainly placed in the basal bone, perhaps less prone to be

resorbed compared to the alveolar bone• Using longer abutments, of course with focus on function prior to esthetics• Patients felt very special to receive this new technique, showing full

compliance

28 years of follow-up



Figure 4.1.4


were not treated. However, these observations need to be analysed further.

Risk of biological complications: calculating the odds ratio/hazard ratioIn an unpublished study by Antoun, Jemt, et al.16, significant risk factors for inflammation (p < 0.05) were analysed using a multivariate logistic regression model in a clinical series of 1,592 operations from 2000–2011. An odds ratio (OR) for early inflammation and hazard ratio (HR) for peri-implantitis were calculated, with the following conclusions:

� the number of implants is linked to the level of associated disease (more implants = more teeth lost = more systemic/local factors)

� a history of periodontitis was a strong predictor of the occurrence of peri-implantitis between 0.4–1.4 years after treatment, but not later

� smoking doubles the risk of early and late complications

� with regard to patient age at the time of surgery, the OR for early inflammation was at its highest at 53 years

� complex surgical techniques involving grafting; the use of membranes; and one-stage and immediate implantation lead to an increased OR for early inflammation and HR for peri-implantitis. This is probably because complex procedures could introduce more foreign bodies to the surgical site

� the risk of peri-implantitis increases as the year of treatment progresses from 2000–2011

The data suggests that the presence or absence of peri-implantitis is linked to multiple factors, such as the nature of the individual’s physiology and the surgical technique adopted. In addition, it has also been postulated that some patients may have a genetic predisposition to inflammation associated with tooth loss.

Incidence of implant failuresIn a 27-year retrospective study17 of 8,528 consecutive cases involving 39,077 implants, 9.8% resulted in failures. Most of these failures were early and related to the same patients. The marked difference between jaws disappeared when moderately rough surfaces were used. When comparing results at 10- and 27-years, higher rates of failure in the following cases were no longer evident:

� the upper jaw � turned surfaces � partially edentulous patients

When the follow-up was extended from 10 to 27 years, incidence rates became balanced, and curves became parallel (see Figure 4.2.3).

Odds ratio/hazard ratio for early and late implant failuresSmoking was seen to double the incidence of both early and late failures.

16 Antoun, Jemt et al. 2016, in manuscript17 Jemt et al. Clin Implant Dent Rel Res 2014

The risk of failure could also be linked to surgical techniques. Immediate implants; cases involving grafting; and one-stage procedures all had a higher OR/HR for both early and late failures18.

The speaker used examples of different clinical variables to demonstrate how a range of risk factors can impact implant failures:

� scenario 1: an immediate implant is placed by the year 2000 in a smoker, with simultaneous grafting surgery

� scenario 2: a non-smoker receives an implant by the year 2010 using a two-stage surgical protocol without immediate grafting

When the four factors were simultaneously present (scenario 1) the risk of failure rose to 36.5% and when none were present (scenario 2) it fell to 0.4%.

Why are there such differences in failures?Younger edentulous patients exhibit higher mortality rates, whereas older patients have a lower mortality rate compared with the general population. This observation seems to reflect variations in general health, which may be more compromised in the younger group than in the older.

Further, younger edentulous patients with implant failures show a higher mortality rate than other implant patients of comparable age. The same is true for older patients. These patterns signal a systemic problem, leading to an impaired osseointegration response. Osseointegration is, in the end, a foreign body response which is regulated by the immune system.

Incidence of peri-implantitis and peri-implantitis surgeryThe risk of developing peri-implantitis was found to be significantly higher (p < 0.05) in the lower jaw; following more advanced surgical procedures; and in cases treated towards the end of the period 2000–201119. Differences in patterns of results between the two clinics could potentially be due to the different choices of surgical techniques used in the different settings.

Analysis of data relating to patients who received public dental care in the Västra Götaland region showed that of 423,000 adults examined in 2014, 2.5% (10,603) had received implant treatment. The mean incidence of peri-implantitis was 7.3%. Only 13.7% of those previously diagnosed with peri-implantitis – 1% of the total implant patient cohort – underwent peri-implantitis surgery. These findings suggest that the prevalence of peri-implantitis depends on how we define the problem. Furthermore, the evolution of the condition is unpredictable with or without surgical treatment.

18 Fransson et al. COIR 200819 Fransson et al. COIR 2008


“All lost” Upper Jaw Turned surface

Lower Jaw Turned surface

25 years follow-up data on patients with turned surfaces

doesn’t indicate an increased risk

25 years followon patients with

doesn’t indicate an

3.7%

9.4%

18.5%

0.4%

1.0%

5.5%

Implant failure (25 yrs CSR / Life Tables )

Jemt et al, prel data 2016

What I learned in 1979 and what I believe I know today

• “Implants may be acceptedby the immune system”

• “Think biology”

• Healed implant sites• Allow time for osseointegration; 2-stage• If grafting; only autologous, allow to heal• Not remove abutments after surgery• No probing• Abutments above mucosa• Only Titanium in contact to bone/mucosa • Design for optimal access for cleaning

• “Biology more important than esthetics”

“Esthetics cost biological health”

1984

1985

2004; 19 yrs

2004; 19 yrs

How many tooth/implant abutments survive?

Teeth versus implants(singel tooth/implant treatment)

After 10 years

98.2%

78.0%

After 1 year

How many tooth/implant abutments survive?

Teeth versus implants(singel tooth/implant treatment)

99.6%

98.5% What do you expectafter 1st year?

Figure 4.2.1

Figure 4.2.2

Figure 4.2.3

Figure 4.2.4

Conclusions from 1979 to the present � we are now more aware of the role of the immune

system in how patients respond to implant treatment. Systemic elements have to be taken into account

� generally speaking, conservative techniques are safer and involve fewer failures. One-stage immediate implantation and simultaneous grafting increase early- and late-stage risks

� we can identify different patterns and levels of complications in different routine practices. It is likely that these differences relate to who decides which patients to treat and what procedures they receive

� there is a trade-off between more complex procedures that can yield optimal aesthetic results and increased risk of complications (Figure 4.2.4)



Contest by the Junior Committee: ‘7 minutes to convince’An original concept to present new research in implant dentistryThe session featured seven ‘out-of-the-box and original’ presentations which each lasted seven minutes. At the end of the session the audience and the Junior Committee voted for the best presentation.

Digital working in implantology (parts 1 and 2)Karim Dada and Leon Pariente

The digital generationImplant treatment should ideally be simple to execute and provide an excellent aesthetic outcome. To achieve this, we must carefully manage the treatment process from start to fi nish. Digital technologies currently provide the best tools for achieving ideal 3D placement of implants (Figure 5.1.1).

Once information about the morphology of the teeth and tissue has been digitised it can be converted to a digital model, and a diagnostic wax-up created. Smart Fusion technology1 can combine CBCT-based data with stereolithographic surface data of the cast from 3D optical scanning. This allows us to visualise the gingival margin of implant sites while using the software for planning, enabling ideal 3D positioning of the implant shoulder. The digital plan is then transferred to the surgical setting using tooth-supported stereolithographic templates. Thus simplicity, effi ciency and predictability can be assured every time.

Positional inaccuracies can compromise aestheticsPositional inaccuracies during implant placement can signifi cantly compromise aesthetic outcomes

1 Smart Fusion. Nobel Biocare Services Inc.

in the anterior maxilla. It has recently been shown that guided implant surgery may increase the predictability of favourable emergence profi les and soft tissue aesthetics assessed by the PES (Pink Esthetic Score)2. The speakers are in the process of publishing a 22 patient series involving 33 implants using image-fusion stereolithographic templates and PES evaluation which supports these fi ndings (Figure 5.1.2).

Strategic extraction protocol (SEP)3

Patients with failing dentition are now demanding implant-supported restorations without the use of an interim removable denture. To facilitate this transition, a strategic extraction protocol (SEP) can be applied. SEP goes a step beyond the ‘dual scan protocol’ as it allows prosthetically driven planning of the implants without the use of a radiographic scan template for the CBCT. Specifi c hopeless teeth are used as abutments to stabilise the surgical guide. They are then extracted in the same surgical session before the installation of the fi nal fi xed prosthesis (Figure 5.1.3).

2 Fürhauser et al. Clin Implant Dent Rel Res 20153 Dada et al. J Prosthet Dent 2016

2 0 1 6 Digital technologies

1 2

3

4

5 6 7

11 22

4

5 6 73

P.E.S BEFORE TREATMENT : 12

P.E.S AFTER TREATMENT : 13 Dada K., Pariente L. in process Implant Dentistry


The conometric concept to make fi xed implant-supported restorationsMarco Degidi

Avoiding problems associated with cement and screwsCement- and screw-retained restorations have limitations, and are prone to both biological and technical complications. The speaker proposed a novel approach for constructing fi xed restorations which may avoid these problems: the use of conometric abutments.

With this approach, retention is achieved via the conical interface – or ‘coupling’ – between abutments and copings. Conical coupling can only occur when the coping is fully seated on the abutment, which is done by gently tapping it (Figure 5.3.1). Its retentive strength has recently been studied in vitro and found to be comparable with – and sometimes superior to – values reported for commonly used temporary cements. The strength of the retention increases with larger abutment diameters and higher head heights4. Conometric retention has the potential to provide a reliable connection between abutments and fi xed prostheses without the need for cement5.

When should we use it?Conometric retention can be used in single, partial and full-arch cases and is compatible with virtually all prosthetic materials (acrylic, metal-ceramic,

4 Nardi D. Int J Prosthodont, 2017 in press5 Degidi et al. Int J Periodont Res Dent 2016

lithium-disilicate and zirconia). The method can also be used for immediate and delayed loading, and can be incorporated into a digital workfl ow. In cases involving two or more implants, good parallelisation among the abutments must be achieved.

The margins of the restoration can be as deep as required, as there is no gap or cement. This allows the emergence profi le to result from the design of the crown or bridge sculpting the soft tissue. This concept is the opposite of digitally designed anatomical abutments.

This novel approach allows easy removal of the prosthesis for maintenance by means of a spring bridge remover. It can then be tapped back into position. The removal can only be performed by the dentist (Figure 5.3.2).

In conclusion, the advantages of this new method of prosthetic retention are:

� it is highly precise � the procedure is simple � it offers a reduced treatment time � it provides good passivity � it is reliable � it is repeatable � the cost is not prohibitive

STRATEGIC EXTRACTION PROTOCOL

Figure 5.1.3


5,7°


A customised solution for 3D defectsGiuseppe Lizio

Standard solutions for treating 3D defects have limitations, and can often prove diffi cult to apply, partly because each defect and patient is unique. Treatments should therefore be customised to meet individual patients’ requirements.

The current approachThe anatomical site and the dimensions and morphology of bone defects can infl uence both the approach and outcome of a grafting procedure:

� autogenous bone blocks: the graft should be oversized to counteract the associated high rate of resorption. Further, autogenous bone blocks are diffi cult to fi t and properly fi x to the defect, requiring a large amount of bone

� titanium mesh in GBR procedures: Ti meshes ensure adequate space; hold the particulate graft material in place; and provide support for the overlying soft tissues. Good results can be obtained in terms of bone volume6, and high implant success rate have been reported7

6 Lizio et al. IJOMI 20147 Pieri et al. J Periodontol 2008; Corinaldesi et al. IJOMI

2009; Minamoto et al. Clin Implant Dent Rel Res 2012; Lizio et al. IJOMI 2016; Pellegrino et al. J Periodontol 2016

The new approachCustomised meshes produced using CAD/CAM may reduce surgical time (Figures 5.4.1 and 5.4.2). The speaker described the procedure used during his recent trial of CAD/CAM produced titanium meshes:

� virtual 3D models of the alveolar defect were constructed with dedicated CAD software using data from CT scans

� each mesh was digitally designed to fi t the bone perfectly, so that further modifi cations would not be required

� meshes were printed with a laser sintering technique and were applied directly to the surgical site

� preliminary results are encouraging

Compared with other augmentation techniques, this procedure has three advantages:

� surgical time is reduced � less bone harvesting is required � the learning curve is shorter

Good levels of bone gain can be achieved if proper management of soft tissue is performed.


Complications Bone regeneration Implants’ results


Eff ective implant surface decontamination during peri-implantitis treatment: what is the secret?Brenda Mertens

According to conclusions drawn in the consensus report of the 6th Workshop on Periodontology8, the key to success in treating peri-implantitis is the chemical and mechanical decontamination of implant surfaces. This is a prerequisite for the elimination of biofi lms. A technique to do this which preserves the structure of the implant; is biocompatible; easy to use; and cost effective is required.

The speaker summarised the results of a systematic review9 of the methods currently used for implant decontamination when treating peri-implantitis which do not harm implant surfaces (Figure 5.5.1). Results were categorised by type of implant surface and treatment approach, with colours indicating

8 Lindhe & Meyle J Clin Periodontol 20089 Mertens et al. in preparation

their success. The authors of the review analysed the three techniques that are most effective for all surface types, and proposed a unique protocol which is valid for all situations (Figure 5.5.2):

Stage 1 – mechanical:

� curettes for removal of granulated tissue � use of air powder abrasive or titanium brushes or

Er:YAG laser

Stage 2 – chemical:

� treatment with cotton pellet soaked with chlorhexidine 0.2% or hydrogen peroxide 5% followed by saline solution

� rinsing with saline solution

Point of view perspective of a dental implant patientMustafa Ozcan

It may seem unusual for a dentist to put him or herself in the place of the patient, but it is a practice that we may all benefi t from. The speaker showed a video fi lmed from the point of view of a patient, illustrating what they were seeing and experiencing during implant surgery. The footage showed what the patient saw at different stages during the treatment, and displayed heart rate readings while processes such as milling or suturing were carried out.

The speaker is currently conducting a study comparing patients’ preoperative anxieties to postoperative pain by means of a visual scale questionnaire (VAS). The results highlight a

signifi cant correlation between anxiety and pain: the more anxious the patient was before surgery, the more pain they experienced afterwards.

The fi lm showed interviews with two patients who experienced different levels of preoperative anxiety. It concluded that patients are unique, experiencing different emotions throughout treatment. Being aware of patients’ perspectives and keeping their personal experiences in mind means we can adjust our behaviour to improve the subjective aspects of treatment and patient satisfaction (Figures 5.6.1 and 5.6.2).

Treatments

Surfaces

Titanium brush

Air-powder abrasive +

rinsing

Laser Er:YAG

Ultrasonic scaler and

metal curette

Ultrasonic scaler and titanium curette

Implantoplasty

Soaked gauze with CHX 0,2%

30s. or H2O2 then

saline

Solution CHX 0,2%

30s. ou H202 5%

Cotton pellet with CHX 0,2%

30s. or H2O2 then

saline

Citric acid

Machined

Plasma Sprayed

Sandblasted or Acid-etched +/-

crystalline deposition

Sandblasted and acid-etched

hydrophilic or hydrophobic

Anodic oxydation

Green : ideal Yellow : acceptable Orange : to avoid Red : not recommended

• Curettes for granulation tissue removal • Air powder abrasive or titanium brushes

or Er-YAG Laser • Cotton pellet soaked with CHX 0,20% or

H2O2 5% then saline • Rinsing with saline

Proposition of a unique protocol for implant surface decontamination

1. Mechanical

2. Chemical

Figure 5.6.1

Figure 5.5.1

Figure 5.6.2

Figure 5.5.2

Mertens et al. (Publication in progress)


Voids and areas of reduced mineralisation in healed sinus grafts: a prospective study using immediate and 6 months’ cone beam computerised tomographyAmandine Para

Previous studies reviewing sinus augmentation have provided histological information; data on rates of implant survival; and/or quantitative evaluations of the volume of bone obtained after grafting.

It is common to fi nd voids or areas of reduced mineralisation following these procedures, however, but this is not refl ected in the studies (Figure 5.7.1). The speaker presented a study examining the qualitative radiological changes in augmented bone after a 6-month healing period. The methodology compared postoperative CBCT scans with a CBCT scan taken up to 6 months after the graft was placed. Different image patterns were found, and were

classifi ed into four groups (A, B, C and D) (Figures 5.7.2–5.7.5).

In 22% of the cases – groups C and D – CBCT images revealed an irregular pattern in the graft, showing voids and zones of radiolucency. These defects were not caused by poor compaction of the material but by defective bone formation in some areas.

In 4% – group D – the graft was non-homogeneous and had an irregular, disordered pattern. The speaker speculated that a postoperative haematoma or infection could have generated tissue granulation instead of bone formation.


Figure 5.7.4

Figure 5.7.5

Figure 5.7.3

Have you ever seen this? Have you ever seen this

GROUP A (n=67) good homogeneous aspect of the graft

GROUP B (n=58) presence of an area of reduced mineralization GROUP B (n=58) presence of an area of reduced mineralizationGROUP B (n=58) presence of an area of reduced mineralizationGROUP B (n=58) presence of an area of reduced mineralization GROUP C (n=29) irregular aspect of the graft and area of radiolucency GROUP C (n=29) irregular aspect of the graft and area of radiolucencyGROUP C (n=29) irregular aspect of the graft and area of radiolucencyGROUP C (n=29) irregular aspect of the graft and area of radiolucency

GROUP D (n=7) disturbed and non-homogeneous aspect of the graft homogeneous aspect of the graftGROUP D (n=7) disturbed and nonGROUP D (n=7) disturbed and non homogeneous aspect of the graft

ResultsAt the end of the session, Mustafa Ozcan won the audience vote. You can watch his video on patient points of view on YouTube:

https://tinyurl.com/j8dxoym


Treatment planning session: a clinical case with a ‘complex’ problem or involving extensive rehabilitationTwo teams of three clinicians – each specialising in a different area of implant dentistry – discussed a complex case presented by the moderator. Details of the case, which had been selected because of its complexity and scope for a multidisciplinary approach, were circulated to the participants before the session.

After an initial presentation of the patient data, both teams proposed their treatment plan and described their decision-making process to support it. This gave the audience an insight into how comprehensive and interdisciplinary treatment plans can be developed. A team from North America and a team from Europe each discussed the approach they would take.

Case presentationSession coordinator: Stefano GracisSession moderator: Michael CohenCase presenter: Andrea Ricci

The patient is a 54-year-old male with severe chronic periodontitis. He is partially edentulous; has diffi culty chewing; complains of mobility of his frontal teeth; and wants to improve his smile. Radiographs taken during his fi rst consultation

show generalised bone loss which is mostly horizontal (Figures 6.1.1–6.1.3). He has a history of periodontitis, and had three implants placed three years ago (Figure 6.1.4). The patient’s periodontal charts can be seen in Figures 6.1.5–6.1.6.





The clinical decision-making process for extraction and implant placementTeam North America: Sonia Leziy, Brahm Miller, Drew Ferris

Evaluating the problemAn important factor to bear in mind from the outset is that the patient wishes to keep as many teeth as possible. There are several questions which need to be answered as part of the initial decision-making process:

� what treatment options can fulfil long-term functional and aesthetic requirements?

� can the natural dentition be maintained, or should implants be considered?

� how good is the patient’s oral hygiene? � is the patient sufficiently motivated and

committed to long-term maintenance? Will this affect the success of the treatment?

After an inter-disciplinary diagnostic review which took restorative, periodontal, orthodontic and occlusal aspects into account, the team focused on risk factors. They emphasised that this step is crucial as it determines the likelihood of disease redevelopment.

Risk factors were categorised as:

� biologic/environmental » advanced periodontal disease » prior implant failures » malocclusion and lack of posterior support

� behavioural » poor oral hygiene and high bacterial burden/

biofilm » potential challenges to adhere to long-term

therapy » unclear history of relevant social habits

� financial/personal » motivation and financial situation » ability to meet patient’s aesthetic expectations

� health/genetic » disease predisposition (IL-1 phenotype, stress,

male gender, diet)

With regard to the patient’s motivation and financial situation, we must ensure that he understands the condition fully and that we manage his aesthetic expectations. Finally, health risks should also be taken into account, especially any genetic disorders.

Following an interdisciplinary patient evaluation, the teeth should be analysed individually. The prognosis of each tooth should be classified as either: favourable, questionable, unfavourable or hopeless. This will help decide whether to conserve or extract (Figure 6.2.1). Making an evidence-based decision is difficult, however, as there is currently no standardised and meaningful system in place for classifying individual teeth1.

1 Samet & Jotkowitz. Quintessence 2009

Options for the maxillary arch (Figure 6.2.2)1. Extraction of all teeth, followed by an implant-

based restoration 2. Conservation of teeth using periodontal and

orthodontic treatment, followed by posterior implants or a removable prosthesis

The rationale behind each optionOption 1 – for:

� the patient presents with advanced periodontal disease

� extraction simplifies the process of aesthetic rehabilitation

� anticipated costs are lower than for other options

Option 1 – against:

� the patient has indicated that he would like to keep his teeth; extraction goes against this

� the risk of peri-implant diseases will persist if the patient does not comply with long-term maintenance

Option 2 – for:

� this option complies with the patient’s wish to preserve teeth

� if a posterior support can be established, function will improve and secondary occlusal trauma will be eliminated

Option 2 – against:

� treatment is prolonged and extensive � removable prostheses can be associated with:

endodontic risks; poorer aesthetics at the tissue-teeth interface; and greater complexity involved with the perio-prosthesis

� peri-implant disease risk

Discussion of option 1 (Figure 6.2.3)It is widely accepted that tooth mobility can be indicative of bone level deterioration in the near future2. Therefore, after an initial period focusing on reducing plaque burden and assessing patient compliance, it was proposed that all remaining teeth be extracted. The restorative solution may then involve All-on-4 or -6 implants. Alternatively, the use of segmental bridges on 8 implants was also suggested. This solution has a greater distal span, but involves sinus grafting. Screwed prostheses requiring pink ceramics would be used to allow retrievability. There is currently a lack of consensus regarding the management of mobile teeth. Fuzzy logic has been proposed as an appropriate means of handling imprecise values like this3.

2 McGuire &, Nunn. J Periodontol 1999; Nieri et al. J Periodontol 2002

3 Mago et al. In: Software Tools and Algorithms for Biological Systems. Springer NY. 2011


Discussion of option 2 (Figure 6.2.4)Periodontal surgery in conjunction with orthodontic treatment has the potential to improve bone levels through tooth alignment; improved force distribution; improved crown to root ratios; and diminished mobility. An interdisciplinary orthodontic-periodontic-implant-prosthodontic approach could drastically improve function, aesthetics, occlusion and periodontal condition4.

Option 2 aims to conserve and is predicated on:

� no extractions � periodontal therapy followed by reassessment � placement of implants in posterior zones using

sinus grafting � orthodontic aligner therapy � polymethyl methacrylate (PMMA) provisional

restorations, either individualised or splinted � a fi nal prosthesis

A preoperative aesthetic risk assessment (ERA)5 is highly recommended during this procedure to improve communication and prevent misunderstandings with the patient.

4 Gkantidis et al. J Oral Rehab 2010; Feng et al. Angle Orthod 2005

5 Dawson & Chen. The SAC Classifi cation in Implant Dentistry. Ed. Quintessence, 2009

The orthodontic objectives of this approach are to:

� intrude the anterior teeth to reduce occlusal forces, which will contribute to more predictable restorations

� take a conservative approach to tooth preparation � achieve a favourable inter-incisal angle using

lingual root torque; this would result in less force and better function

� correct the patient’s midline and class II malocclusion on the left

� align the teeth to manage the space for future ideal restorations

In this case the use of aligners instead of traditional braces is preferable, as they are associated with improved patient acceptance and a periodontal environment which is easier to maintain. Aligner therapy offers distinct advantages for patients treated at a distance6 (Figure 6.2.5). Provisional PMMA restorations would be used, as they offer the opportunity to refi ne occlusal adjustments, and the prosthesis design can be checked with the patient. In the end the speakers decided to treat with option 2, and their plan is outlined in Figure 6.2.6.

6 Levrini et al. Eur J Dent 2015

chief

concerns

problem list

diagnosis

risk factors

prognosis

our treatment solution

concluding remarks

periodontal stability

extraction necessary

likely

maybe

unlikely

questionable

unfavourable

hopeless

favourable

☠

**** unfavorable - local / systemic factors cannot be controlled **** questionable - local / systemic factors may/may not be controlled **** unfavorable - local / systemic factors cannot be controlled **** questionable - local / systemic factors may/may not be controlled

• Kwok V, Caton JG. Prognosis revisited: A system for assigning periodontal prognosis. J Periodontol 2007;78(11)2063-2071. • Faggion CM, Petersilka G, Lange DE et al. Prognostic model for tooth survival in patients treated for periodontitis. J Clin Periodontol 2007;34: 226-231.

rationale periodontal disease advanced aesthetic rehabilitation complex if teeth are kept anticipated cost lower

negatives patient not receptive to extractions risk for peri-implant diseases if non-compliant

rationale patient does not want to lose teeth establish fixed posterior support & improve aesthetics/function

all teeth extracted & implant based restoration no extractions & perio-pros-ortho & posterior implants or RPD

negatives extensive/lengthy treatment/partly removable sol’n tissue/teeth interface aesthetics, endodontic risks clinician skills . perio-prosthesis implants . extensive surgical requirements . peri-implant disease risk an art … but state of the art?

rationale patient does not want to lose teeth establish fixed posterior support & improve aesthetics/function

negatives extensive/lengthy treatment/partly removable sol’n tissue/teeth interface aesthetics, endodontic risks clinician skills . perio-prosthesis implants . extensive surgical requirements . peri-implant disease risk an art … but state of the art?

tooth mobility at the beginning of treatment… indicative of a poorer prognosis at 5 years• McGuire MK, Nunn ME. Prognosis versus actual outcome. IV. The effectiveness of clinical parameters and IL-1

genotype in accurately predicting prognoses and tooth survival. J Periodontol 1999;70:49-56.

presence of mobility (in periodontal patients) was strongly associated with bone level deterioration

• Niece M, Muzzi L, Cattabriga M et al. The prognostic value of several periodontal factors measured as radiographic bone level variation: A 10-year retrospective multilevel analysis of treated and maintained periodontal patients. J Periodontol 2002;73:1485-1493.

rationale avoid removable prosthesis throughout treatment cost-effective solution transition zone considerations & ridge reduction avoid sinus/reduce surgical exposure/cost & time

initial periodontal therapy . treatment partial denture . reassessment . flap curettage . reassessment 15/16 implants and transcrestal sinus graft

24-27 ridge augmentation and lateral window sinus graft . delayed implants 25-27 orthodontic aligner therapy

prolonged time . PMMA provisional restorations . individualized or splinted if necessary for mobility definitive restoration FPD 13-11 (or implant 12). dentition. trans-Zr .5 wall. implants screw-retained monolithic zirconia

similar periodontal case treated with aligners

aligner advantages vs. traditional braces

c l e a r a l i g n e r p a t i e n t s s h o w s u p e r i o r o v e r a l l p e r i o d o n t a l h e a l t h

c o n t r o l l e d f o r c e s / b e t t e r h y g i e n e c o m b i n e d w i t h p e r i o t r e a t m e n t c r e a t e f a v o u r a b l e c l i n i c a l a t t a c h m e n t

c a n t a i l o r a p p o i n t m e n t f r e q u e n c y d e p e n d i n g o n p a t i e n t d e s i r e s

s p l i n t i n g e f f e c t

i m p r o v e d c a s e a c c e p t a n c e

L e v r i n i L , M a n g a n o A , M o n t a n a r i P e t a l . E u r J D e n t 2 0 1 5 J u l - S e p t ; 9 ( 3 ) : 4 - 4 - 4 1 0 . M e l s e n B , A g e r b a e k N , E r i k s e n J E t A l . J O r t h o d D e n t o f a c O r t h o 1 9 9 8 , 9 4 : 1 0 4 - 1 6

or fpd

C C C C CPMMA restorations

then definitive restoration

CCC Cmandibular arch treatment phasesinitial therapy /OHI/reevaluationbone graft/posterior implants & flap curettageorthodontics. aligner therapylong term PMMA reinforced provisionals 33-43definitive restoration for aesthetics/functionpossible implants 32/42 & fpd or 32 & crown3 month SPT & aligner retention

maxillary arch treatment phasesinitial therapy/OHI/reevaluation/treatment partial dentureprobable flap curettageridge augmentation & posterior implantsorthodontics. aligner treatment long term PMMA provisionals - dentition & implantsdefinitive restoration for aesthetics/function3 month SPT & aligner retention

PMMA restorations then definitive restoration


PMMA restorations C

implant fpd

?


Figure 6.2.1

Figure 6.2.3

Figure 6.2.5

Figure 6.2.2

Figure 6.2.4

Figure 6.2.6


Clinical decision-making processTeam Europe: Rino Burkhardt, Jörg Strub, Marc Schätzle

PrognosisThe patient’s concerns and wishes must be addressed from the outset. First, a pre-therapeutic prognosis must be determined for each individual tooth. However, this is an area of controversy as practice currently varies between dentists and depends on their individual preferences. This lack of clarity is due to the relatively imprecise defi nition of hopeless teeth. To further complicate matters, it has been shown that regenerative therapy has the potential to change the prognosis of hopeless teeth7.

During the initial phase (which focuses on improving oral hygiene) pocket depth and tooth mobility are considered to be prognostic indicators. Before treatment can progress to the corrective phase, a re-evaluation must be performed to demonstrate that pocket depth and bleeding have been reduced, and that measures to control plaque have been effective.

Orthodontic phaseThe aims of the orthodontic phase were to:

� align the upper dental midline to the facial midline

� intrude anterior teeth by 4mm to the cementoenamel junction (CEJ)

� correct torque in the upper incisors

To achieve these aims, the speakers proposed using fi xed appliances and a palatal implant for reinforced anchorage.

7 Becker et al. J Periodontol 1984; McGuire & Nunn. J Periodontol 1996; Cortellini et al. J Clin Periodontol 2011

If the periodontitis proves to be uncontrollable, intrusion could lead to further breakdown of the alveolar bone. Conversely, if the long junctional epithelium is healthy, intrusion can result in the coronal displacement of attachment levels and result in better distribution of forces throughout the teeth8.

A palatal implant would provide absolute anchorage while distalising teeth 24–23 by about 4mm until class I malocclusion could be reached. Palatal implants have been shown to have a statistically signifi cantly lower risk of failure than mini-screws9. In the meantime, two implants could be placed in each upper posterior quadrant (Figures 6.3.1 and 6.3.2). In the lower arch, the use of a removable bite plate was suggested to move tooth 37 to an upright position and reduce wobbling in the lower incisors.

Prosthetic restorationThere is no clear evidence as to when this stage should begin. A review of the literature only revealed case reports with vague and varying recommendations:

� 8 weeks after removal of the active appliance � once adequate retention is obtained � after approximately six months

Retention could be achieved using a fi xed appliance placed during the prosthetic phase or with bonded stainless steel retainers. In the meantime, implants in the mandible could be placed, combined with lateral soft tissue augmentation.

8 Melsen et al. Am J Orthod Dentofac Orthop 1988; Melsen B. Eur J Orthod 2001

9 Schätzle et al. COIR 2009

• Insertion site determined by the subsequent use of the implant as a prosthetic abutment

• Positions within the alveolar process and number of implants selected by the reference of prospective final tooth position

• Tooth 15 in Cl. I position will be maintained• Teeth 23 and 24 will be distalized approximately

4mm into Cl. I relation

Treatment Planning – upper jaw

• Insertion of endosseous implants in the upper jaw

Treatment Planning – upper jaw

• Insertion of endosseous implants in the upper jaw

Treatment Planning – lower jaw

• Relieve incisors from jiggling• Uprighting 37 by means of a removable biteplate at a later time point

Figure 6.3.1

Figure 6.3.3

Figure 6.3.2


Case completionAt the end of the session, the moderator revealed the actual course of treatment, which had involved extraction of the maxillary teeth and use of an implant-supported total prosthesis in the upper jaw.

The planning stage had started with a digital smile design process. This ensured that the patient’s midline, incisal length and occlusal plane were correct from the early stages of the treatment, and would fit the smile line and the face. This process was also used as a communication tool to allow the patient to better understand the treatment objectives. The moderator emphasised that the patient was informed of the risks, and was fully compliant.

After an initial period of non-surgical periodontal therapy followed by a re-evaluation appointment, the prognosis was:

� poor for all maxillary teeth, as well as the upper implant

� fair for mandibular anterior teeth � good for right posterior implants and the

mandibular left molar, providing a root separation procedure

Full extraction of the maxillary teeth was performed and eight implants were placed in the extraction sockets. After six months, a second surgical phase was observed to gain access to the implants. A full upper arch provisional was delivered after tissue healing. During the osseointegration phase of the maxillary implants, implants were placed in the edentulous sites in the mandibular arch. At the patient’s six month re-evaluation he was satisfied with function, but complained (as expected) of some food trapping and difficulty in

pronouncing ‘F’ sounds. The final treatment plan was therefore confirmed in favour of a maxillary implant-supported overdenture. A few months after delivery of final restorations, the patient expressed a desire to reduce the black triangles between the mandibular anterior teeth. He requested a minimally invasive treatment. Reshaping of the mandibular anterior teeth was performed by means of direct composite restorations.

Treatment remains stable after nine years. To date, the only modification required has been the recent replacement of the acrylic resin and upper teeth since the old ones had become worn.

Conclusion � the same case can be treated in a variety of

ways; more than one approach can often achieve clinical success

� the patient’s needs, wishes and levels of commitment must be taken into account

� we should be aware of our own clinical expertise and technical limits in order to develop an evidence-based treatment plan that is within our capabilities

� every step must be planned carefully, including placement of temporary prostheses and overall timeline

� potential risks should be considered and shared with the patient

� the treatment plan should be discussed in detail with the patient, and they must give informed consent

� an interdisciplinary approach is highly recommended to achieve the best possible results

� complex cases require a constant re-evaluation of patient compliance


Treatment planning away from biological and technical complicationsRalf Kohal

Can we trust dental implants?The speaker began with a surprising question: ‘Can we trust dental implants?’ He went on to say that several systematic reviews have concluded that the survival rate of implant prostheses is generally high. In cases involving single crowns, implant survival rate at fi ve years is 97.2%, and at ten years is 95.2%. In cases involving fi xed partial dentures, the fi gures are 95.6% and 93.1 % respectively1.

Based on this, he went to conclude that ‘Yes, we can trust dental implants’. Nevertheless, he emphasised that the risk of complications is always present, and the patient must understand that treatment does not end once the prosthesis has been installed (Figure 7.1.1). Factors which infl uence the incidence of complications are many and varied, and are therefore diffi cult to control2.

Crown/implant ratioIt is widely accepted that short implants with long crowns are not associated with marginal bone loss. There is general consensus, however, that this combination has the potential to lead to technical complications. We should carefully manage these cases in order to limit occlusal forces:

1 Jung et al. COIR 2012, and Pjetursson et al. COIR 2012, respectively

2 Chrcanovic et al. J Oral Rehab 2014

SESSION 5 Treatment planning away from biological and technical complications

Jung et al. 2012 Pjetursson et al. 2012

Results: 66.4% of patients free of any complication

• biological complications: • 5-year observation with periimplantitis/soft

tissue complications of 8.5% • rate of implants with substantial bone loss (>

2 mm) of 2.6% • technical complications:

• 5.3% abutment or occlusal screw loosening • 4.7% for loss of retention in cemented FDPs • 13.5% fracture of veneering material (7.8%

for PFM, 20.2% for acrylic veneering material)

• 5.4% loss of screw access hole restoration • 1.3% abutment or screw fractures • 0.5% implant fractures and framework

fractures

Results • biological complications:

• 5-year cumulative soft tissue complication rate of 7.1%

• cumulative complication rate for implants with bone loss >2 mm of 5.2%

• technical complications: • 8.8% for abutment and screw-loosening • 4.1% for loss of retention • 3.5% for fracture of the veneering material

(no differences between all-ceramic and PFM crowns)

• 1.3.% fracture of the framework material • 0.4% for abutment or screw fractures • 0.18% for implant fractures


Author SC Material Survival Observation period Veneer Chipping

Spies et al. (2016b) SC All-ceramic (lithium-disilic) 100% 3 years 0% (eMAX)

Spies et al. (2016a) SC All-ceramic (Zr-based) 100% 1 year 18.2% (VITA VM9)

Nejatidanesh et al. (2016) SC All-ceramic (Zr-based) 98.7% mean: 5 years 8.2% (Cercon)

Spies et al. (2015) SC All-ceramic (Zr-based) 76.6% 5 years 42.8% (NobelRondo)

Monaco et al. (2015) SC All-ceramic (Zr-based) 91.2% up to 5 years 4.2% (13 diff. mater.) 2.8% (framew. frac.)

Lee et al. (2015) SC All-ceramic (Zr-based) Metal ceramic

100% 100% 4 years 85%

23%

Kolgeci et al. (2014) SC All-ceramic (Zr-based) 97.5% up to 7 years (mean: 3.3 years)

1.7% (NR, Crea., Cer.) 0.8% (framew. frac.)

Hosseini et al. (2013) SC All-ceramic (Zr-based) Metal ceramic

97% 97% 3 years 4% (Empress, eMAX)

0% Jung et al. (2012)

review SC Metal ceramic / All-ceramic 96.3% 89.4%

5 years 10 years 3.5% (AC/MC)

Schwarz et al. (2012) SC All-ceramic (Zr-based) Metal ceramic

86.8% 98.3% 2.1 years 24.5% (Cercon Kiss)

9.5%

Nothdurft and Pospiech (2009) SC All-ceramic (Zr-based) 100 % 6 months 7.5%

Summary results for veneer chipping for the different implant-supported reconstructions and materials


Author FDP Material Survival Observation period Veneer Chipping

Spies et al. (2015) FDP All-ceramic (Zr-based) 100% mean: 2.5 years 23.1% (ZirPress)

Pozzi et al. (2015) FDP (full-arch) All-ceramic (Zr-based) 100% mean: 3.5 years

> 3 years 1.4% (11%) (CZR)

Konstantinidis et al. (2015) FDP All-ceramic (Zr-based) 100% mean: 2.7 years 71%

Spies et al. (2015) FDP All-ceramic (Zr-based) 93.8% 5 years 62% (NobelRondo)

Esquivel-Upshaw et al. (2014a) FDP All-ceramic (Zr-based) Metal ceramic

97.2% 100% 2 years 16.7% (e.max ZirPr.)

11.1%

Esquivel-Upshaw et al. (2014b) FDP All-ceramic (Zr-based) Metal ceramic ? 3 years 14.6% (e.max ZirPr.)

14.6%

Kolgeci et al. (2014) FDP All-ceramic (Zr-based) 95.9% up to 7 years (mean: 3.3 years)

4.1% (NR, Crea., Cer.) 2.7% (framew. frac.)

Larsson & Vult von Steyern (2013) FDP(full-arch) All-ceramic (Zr-based) 100 % 8 years 40 %

Pjetursson et al. (2012)

review FDP

Metal ceramic All-ceramic (Zr-based) All-ceramic (ZTA)

96.5%

5 years (10 years)

7.8%

Larsson & Vult von Steyern (2010) Larsson & Vult von Steyern (2016)

100% 100%

69% (Denzir) 17% (18%) (In-Ceram Zirc.)

Summary results for veneer chipping for the different implant-supported reconstructions and materials

Figure 7.1.1

Figure 7.1.3

Figure 7.1.2

Festival of complicationsDental implants are now being placed in a variety of different clinical circumstances, and by clinicians who are following many different protocols and using different ‘hardware’. This increase in the use of implants has, in turn, led to a rise in the occurrence of complications.

During this session, the speakers discussed factors that play a role in the incidence of complications and how to resolve them. The fi rst speaker discussed complications specifi cally associated with fi xed implant prostheses; the second focused on removable prostheses; the third shared tips and tricks for resolving and avoiding less ideal situations.


� consider the option of splinting, which can prove beneficial when no conical connections are used

� axial forces on functional cusps are preferred; avoid eccentric contacts if possible

� bear in mind that not all implant designs are suitable for an unfavourable implant/crown ratio

Ceramics as restorative implant materialsIt would appear that classical technical problems associated with metal-ceramic prostheses have not been overcome by ceramics. The speaker reviewed veneer chipping in cases involving different implant-supported reconstructions and materials, and found that results varied widely (Figures 7.1.2 and 7.1.3). He concluded:

� the clinical behaviour of hand-layered zirconia is highly dependent on technique and material used

� monolithic lithium-disilicate crowns on zirconia implants show promising results at 3 years

� long-term results for facially veneered monolithic zirconia frameworks are still lacking

� hybrid ceramics with polymer networks and nano-ceramic resin composites are two new and interesting materials, but they lack clinical data

Screw retention versus cementation. Which has fewer complications?A review of the literature yields controversial results3. There is insufficient evidence to distinguish between screw retention and cementation, and the decision ultimately rests with the personal preference of each operator.

With regard to the matter of excess cement, individual abutments with visible clinical margins are highly recommended: the deeper the margin, the greater the amount of concealed cement.

3 Wittneben et al. IJOMI 2014; Ma & Fenton. Int J Prosthodont 2015; Lemos et al. J Prosthet Dent 2016

Removable implant reconstructions: factors influencing incidence and type of complicationsHugo de Bruyn

Implant overdentures in the mandibleDue to improved patient satisfaction and quality of life, mandibular implant overdentures are preferred to conventional dentures, and are considered the

‘minimum standard’ treatment for edentulous patients. This was stated in 2002 at the McGill conference4. Since then, many questions have been raised:

� how many implants should be placed? � what type of connection should be used? � what is the potential for complications and repairs? � what are the costs and benefits? � how can patients be selected to ensure greater

effectiveness?

Reviews illustrated a long-term survival rate exceeding 95%, with good clinical performance and patient satisfaction. Implant number, length and bone quality, as well as the age of the patient, was found to have no impact on implant survival. Ongoing bone loss was documented in only 2.5% of patients, and generally alongside external risk factors such as smoking, or the presence of dehiscence in the initial surgery5. Additionally, a 10-year follow-up study revealed that peri-implant health remained stable, provided that a programme of regular maintenance was followed6.

4 Thomason et al. J Dent 20125 Vercruyssen et al. COIR 20106 Dierens et al. in preparation

Maxillary overdenturesA survival rate of 75% for maxillary overdentures on two first-generation implants was reported after seven years by Bergendal & Enquist (1998). Survival rates increased dramatically when 4–6 implants splinted with a limited resilience bar were used. Furthermore, fewer complications were reported when this type of reconstruction was selected7. On the other hand, more complications were documented in non-splinted maxillary overdentures. This resulted in increased treatment costs over time.

Although initial treatment costs are reduced when two maxillary implants rather than the standard number of four are used to support overdentures, this technique should be used with caution. A recent one-year study8 has recorded various biological and technical complications as a result of this ‘economic’ option. These complications bring with them additional costs, and therefore increase the overall cost of treatment. The speaker therefore advised the use of overdentures supported by two maxillary implants only in cases where a minimally invasive procedure is indicated. Anatomical constraints in the maxilla, such as the presence of the sinus, make it difficult to achieve the required parallelism of the implants and may lead to divergence between them. This situation is further complicated in cases

7 Bergendal & Enquist. IJOMI 1998; Slot et al. JCP 20168 Zembic et al. COIR 2016


involving non-splinted implants, because large discrepancies in implant direction may cause further soft tissue problems and technical complications with the attachments. Enhancing parallelism of the attachment’s insertion direction may be benefi cial by using angulated implants, for example. This is visible in Figure 7.2.1.

Impact of complications on treatment costComplications can infl uence the overall cost of treatment, so preventing them can improve cost-effectiveness. Long-term maintenance and the possibility of complications must both be taken into account, and discussed with the patient from the outset (Figure 7.2.2).

A study currently being carried out at Ghent University has found that over time the annual cost of addressing complications equates to 2.1% of the initial treatment cost, and ranges from 0–14%9.

9 Dierens et al. Unpublished data, Ghent University

An overdenture retained on a single implant in the mandible may be a cost-effective alternative to one that uses two implants due to lower component costs and shorter treatment times. The evidence suggests that patient satisfaction and ease of maintenance are similar10.

Patient-centred outcomes: quality of lifeSuccessive investigations carried out at Ghent University have shown high levels of patient satisfaction with implant-supported prostheses. OHRQoL improvements were observed in all the following categories (see Figure 7.2.3):

� full fi xed � overdenture � single tooth replacement11

10 Walton & MacEntee. Int J Prosthodont 200911 Ghent University PhD theses: Raes 2010, Browaeys 2013,

Dierens 2014

Figure 7.2.1

Figure 7.2.3

Figure 7.2.2


How to solve – or better how to avoid – technical complicationsOliver Brix

The speaker presented several clinical cases in which poor placement of implants had led to soft tissue volume defects. He then outlined how these defects had been masked by appropriate use of pink porcelain.

He then went on to discuss issues relating to porcelain chipping. This can be caused both by the limitations of the material, and the patient’s functional habits. Monolithic zirconia prostheses are stronger and less prone to chipping, but are unable to meet aesthetic requirements in the anterior region. For that reason, the speaker posited that the best solution may be a combination of micro-veneered

monolithic zirconia frameworks with lithium disilicate laminates.

He explained that he favours non-metal reconstructions because of their aesthetic results. For a single-tooth replacement, he proposed covering and cementing a titanium base with a customised zirconia abutment in the lab to be restored with a lithium disilicate cemented crown.

Re-firing porcelain always presents a challenge. A chemical system for cleaning and disinfecting the ceramic is strongly recommended to prevent it from shattering.


Bone biology: where do we stand?This session was devoted to recent advances in bone biology and how they can be applied to osseointegration. The first presentation focused on implant concepts influenced by recent bone research; the second provided new insights into the bone-implant interface; the third painted a modern vision of osseointegration and discussed peri-implantitis.

Cell biology and immune response related to implant dentistryReinhard Gruber

Can inflammation support bone regeneration?1

Inflammation is usually involved in tissue destruction, as, for example, in the case of periodontitis. Transient inflammation, however, is an essential step in the process of bone regeneration and fracture repair. The role and clinical significance of TNFα and COX-2 in bone healing is well established (Figure 8.1.1), and it is recognised that the suppression of early inflammation may in fact hinder bone regeneration.

The role of fibrinolysisFibrinolysis plays an important role in the healing process, as it enables newly-formed capillaries to penetrate the fibrin matrix. Fibrinogen is a key factor in the formation of fibrin; plasminogen is crucial for the process of fibrinolysis and plays a vital role in bone regeneration (Figure 8.1.2). Impaired fibrinolysis may have a negative impact on bone regeneration, so strategies for enhancing fibrinolysis should be investigated. This is especially important in cases which also involve obesity, smoking, diabetes or chronic inflammatory disease, where fibrinolysis is impaired2.

Are macrophages required for bone regeneration?Macrophages are a key component of the mononuclear phagocyte system (Figure 8.1.3). They are found in all tissue-types throughout the body and are extremely versatile, displaying a variety of functional phenotypes depending on environmental signalling. Following tissue damage or infection, monocytes are attracted to the damaged site, where they differentiate into tissue macrophages as

1 Further details of this report are summarised in the recent review by Gruber, Stadlinger, Terheyden: ‘Cell-to-cell communication in guided bone regeneration: molecular and cellular mechanisms’, COIR 2016

2 O’Keefe et al. New Eng J Med 2015

required; in bones, they become osteal macrophages, or ‘osteomacs’.

It has been demonstrated (experimentally) that macrophages control the wound healing process, and also play a key role in the reversal phase of bone remodelling, as well as in bone regeneration. It is now thought that biomaterials can support the differentiation of macrophages into their

‘regenerative’ phenotype.

Can blood vessels provide bone cells?It is widely accepted that blood vessels provide the progenitors of both osteoblasts and osteoclasts. The progenitors of bone-forming osteoblasts are preferentially associated with a specialised population of endothelial cells providing signals that support bone formation and maturation (Figure 8.1.4). Thus, more bone walls in the osseous defect lead to higher levels of angiogenesis, the process by which new blood vessels are made. It is also necessary to provide mechanical stability in the wound in order to facilitate angiogenesis and consequently bone formation.

Insertion torque and osteocytesFar from being the passive cells that we previously thought them to be, osteocytes play a significant role in orchestrating bone formation and bone resorption. They are crucial in the processes of mechanotransduction, mineralisation of the bone extracellular matrix and bone homeostasis, through the modulation of osteoblast and osteoclast activity. Apoptosis of osteocytes triggers osteoclastogenesis including osteocyte-derived RANKL (Figure 8.1.5). Thus, high implant insertion torques can cause increased compressive stress and micro-cracks in the bone, and may trigger osteocyte apoptosis. This can, in turn, result in increased bone resorption (Figure 8.1.6)3.

3 Cha et al. J Dent Res 2015


Reinhard Gruber

Transient inflammation: bone regeneration

Zhang et al. COX-2 … is critically involved in bone repair. JCI 2002 Simon et al. COX-2 … is essential for bone fracture healing. JBMR 2002 Gerstenfeld et al. Impaired fracture healing in the absence of TNF-alpha .… JBMR 2003

day 7

day 14

day 21

WT COX-2 -/-

Reinhard Gruber

Plasminogen is required for bone regeneration

! Kawao et al. JBMR 2013

Yuasa et al. JCI 2015

WT Fbg-/-

Reinhard Gruber

Tissue-resident „osteal“ macrophages

Galli SJ et al. Nature Immunology 2011, Alexander et al. JBMR 2011; Chang et al J Immunol 2008

F4/80 OsteoMac (B) canopy structure over cuboidal

Osteal macrophages (F4/80) Osteoblasts (osteocalcin)

Reinhard Gruber

Blood vessels: Origin of osteoblasts

Sivaraj et al. Development 2016; Kusumbe et al. Nature. 2014

Epithelial cells

Osteoblast progenitors

Nuclei

Reinhard Gruber

Osteocyte apoptosis: bone resorption

Tatsumi S, et al. Cell Metab. 2007

wild type

diphtheria toxin receptor exclusively in osteocytes

PBS diphtheria toxin

Reinhard Gruber

Insertion torque: possible bone damage

Cha JY, Pereira MD, Smith AA, Houschyar KS, Yin X, Mouraret S, Brunski JB, Helms JA. JDR 2015

Figure 8.1.1

Figure 8.1.3

Figure 8.1.5

Figure 8.1.2

Figure 8.1.4

Figure 8.1.6


Bone to implant interface: where do we stand and where do we go?Peter Thomsen

Tailoring the surface of implantsThe properties of implant surfaces can be modified in order to trigger biological responses. These responses are induced by a series of physicochemical characteristics encoded at macro-, micro-, and nano-levels. Oxidised surfaces, for example, can affect the initial inflammatory phase and promote osteogenic differentiation and osteoclast activity. When compared with machined surfaces, oxidised surfaces promote in vivo a higher degree of mineralised bone apposition on the surface. Apatite can also be detected in sub-micron pores, suggesting bone bonding4.

Cells communicate at the implant surface via exosomesThe adhesion and osteogenic differentiation of mesenchymal stem cells on titanium surfaces is promoted by their co-culture with macrophages, perhaps by means of secreted exosomes. As well as providing soluble factors, exosomes constitute an additional mode of cell-to-cell signalling with an effect on stem cell differentiation during the transition from injury and inflammation to bone

4 Omar et al. J Biomed Mater Res 2010, Biomaterials 2011; Lennerås et al. Clin Implant Dent Rel Res 2015; Palmquist et al. J R Soc Interface 2010

regeneration. Mesenchymal stem cells also release exosomes, which are internalised by other stem cells and trigger osteogenic differentiation and extracellular matrix (ECM) mineralisation. The regulatory effect on osteogenesis by exosomes is partially exerted by exosomal micro-RNA5.

New role of the collagen membrane for GBRThe prevailing explanation for GBR points to the role it plays in providing a barrier against soft tissue invasion. It has recently been observed, however, that inflammatory and osteoprogenitor cells can migrate to the collagen membrane and release factors encouraging tissue/bone regeneration. This is suggested by the similarity between the gene expressions of bone markers in both the membrane and in the remodelling defect6. These phenomena have important clinical implications, and could pave the way for innovative membrane-surface tailoring, which would improve the role of the membrane in bone regeneration by acting as a truly bioactive compartment.

5 Ekström et al. PLOs ONE 2013; Wang X et al. submitted.6 Taguchi et al. Biomaterials 2005; Eigali I et al. Acta

Biomater 2016; Turri A et al. Biomaterials 2016


What is osseointegration in 2016 and why are we losing bone around dental implants?Tomas Albrektsson

‘Peri-implantitis’ – a foreign body reaction or a man-made ‘disease’7

Peri-implantitis is a controversial topic, with a discrepancy between the high reported rates in recent publications and the experience of clinicians. The definition of peri-implantitis as a common infectious disease similar to periodontitis is problematic in several ways.

Fundamental differences between the interface of teeth and implants with bone make them react differently. A study by Becker et al. on the transcriptomic profiling of both concludes that periodontitis and peri-implantitis exhibit different mRNA signatures:

While in peri-implantitis tissue the regulation of transcripts related to innate immune responses and defence responses were dominating, in periodontitis tissues bacterial response systems prevailed.8

A recent clinical study of marginal bone loss in areas surrounding implants and teeth also seems to illustrate this, finding that bone loss in both areas behaved differently9. The authors conclude:

‘marginal bone loss at implants and teeth … might be independent phenomena’. It has been shown that periodontal markers such as bleeding on probing (BoP) and periodontal disease (PD) are not reliable tools for diagnosing implant disease10.

In contrast to periodontitis, the onset of marginal bone resorption around oral implants is unrelated to bacteria or plaque. Rather, it is an aseptic reaction which arises as a complication of treatment. Sometimes it progresses and becomes problematic, and sometimes it remains in equilibrium, dormant for decades (Figure 8.3.1).

There is also evidence that contradicts the allegedly high incidence of peri-implantitis. Jemt

7 Albrektsson et al. Clin Implant Dent Rel Res 20168 Becker et al. Clin Implant Dent Rel Res 20149 Cecchinato et al. COIR 201610 Coli et al. Periodontology 2000 2016; De Bruyn et al.

Periodontology 2000 2016

et al. documented marginal bone levels around implants in the cohort of 182 patients evaluated by Fransson and co-workers 9 years earlier11. They found that 91.4% of the allegedly affected implants had suffered no further significant bone loss than was initially reported, and that 95.3% still survived. The authors offered another intriguing conclusion: ‘Treated patients did not perform better than untreated patients with regard to bone loss or implant failure’. To better understand these issues, we must go back to osseointegration as it was originally conceptualised.

Osseointegration revisitedBody defence mechanisms can respond to the insertion of an implant in two ways: the implant fails and is expelled (primary failure), as happens in 1–2% of cases, or the implant is accepted and becomes encapsulated by a bone envelope. Secondary marginal bone loss depends on immunological phenomena, resulting in a delayed expulsion of the implant or late failure. This remodelling response may result in:

� minor bone resorption taking place over decades � later complications, potentially resulting

in infections � aseptic loosening (Figure 8.3.2)

The balance of osteoblasts and osteoclasts is not only an expression of bone homeostasis, but the cells themselves are also part of the immune system12. Marginal bone loss may be the result of multiple factors that cumulatively activate the immune system (with complement, macrophages, B- and T-cells), tilting the delicate balance between osteoblasts and osteoclasts towards resorption (Figure 8.3.3). However, even if immunological reactions result in bone resorption, we cannot ignore the fact that bacteria may plan an additional role in this process.13

11 Jemt et al. Clin Implant Dent Rel Res 2013; Fransson et al. COIR 2008

12 Takanayagi H. Nat rev Immunol 2007 and Nat Rev Rheumatol 2012

13 Trindade et al. Clin Implant Dent Rel Res 2016


Substantial bone loss observed after thefirst year of implant placement.

Peri-implantitis?Actions?

RESPONSE PROPER:Do nothing at all. This is Marginal Bone Loss but no disease. You cannot base a statement on disease on a single radiogram even if some milli-meters of bone has been lost.

This is a 50-year control of a perfectly functioning implant placed in 1964.Courtesy of Dr Luca Pagliani

Bone loss with infection may follow first many years later in a few cases – most implants will see natural cessation of aseptic loosening without further problems

Dangerous bone loss

With time the delicate balance between the osteoblast and the osteoclast is influenced; osteoclasts dominate and bone resorption follows (Albrektsson, Canullo, Cochran & De Bruyn 2016).

Fortunately, provided the use of clinically documented implants placed by trained individualsproblems with implant threatening bone resorptionis limited to 1-2% of placed devices over follow up times of 10 years or more

Figure 8.3.1

Figure 8.3.2

Figure 8.3.3


Tips and tricks for a successful implant practice

In this session, three factors which can contribute to a successful practice were discussed together for the first time:

� the rapid evolution of knowledge and new techniques means dentists need to be well-trained and stay up to date. The first presentation described the EAO’s new Education Programme which aims to help clinicians meet the current demands of implant dentistry

� the second presentation explored the growing need for photographic documentation in practice, and how to use dental photography to document and communicate treatment

� the final presentation looked at practice management and provided insights and tips on developing a successful strategy for this

Introduction to the EAO Education ProgrammeHelena Francisco

The EAO and educationThe EAO’s vision is ‘to improve the quality of patient care by bridging the gap between science and clinical practice’1. One of the ways it works towards this aim is through educational initiatives.

In 2010, the EAO launched its Certificate in Implant-based Therapy to establish an appropriate international standard of competency, and to support high-quality practice via accreditation. From 2015 onwards, the EAO has also been organising Master Clinician Courses which focus on a variety of subjects in implant therapy to improve the expertise of participants.

Now, the EAO has taken a further step, introducing a comprehensive Education Programme which enables candidates to undertake structured learning over a three-year period covering cases at all levels of complexity. The programme combines theoretical knowledge with hands-on courses at some of Europe’s most prestigious universities. Successful candidates receive the EAO’s Postgraduate Diploma in Implant-based Therapy. The programme provides

1 www.eao.org

an additional pathway to attaining the EAO’s Certificate in Implant-based Therapy.

The Education ProgrammeThe complete curriculum comprises 250 hours of theoretical and practical training which takes place over a period of three years. The programme is split into six modules: two per year hosted by different European universities. The breadth of the programme is extensive and covers subjects including surgery; prosthodontics; periodontics; and treatment planning or maintenance in every module.

The level of complexity of the modules is based on the SAC Classification, with two modules at straightforward (S) level; two advanced (A) modules; and two complex (C) modules. This provides an increasing degree of complexity as the programme progresses.

How does it progressEach module begins with preparation through the EAO’s bespoke online learning platform. This is followed by a three-day live learning event (LLE) which combines hands-on elements, lectures, small-group seminars, practical sessions and live surgery. Online mentoring is also provided between


modules, and each participant is paired with one or more expert clinician on a one-to-one or small-group basis. Each group of participants receives approximately eight hours of mentoring. Mentoring sessions are structured around clinical cases that the student is expected to perform and document between each module.

Admission is open to applicants with a dental degree who have been practising for at least two years.

All six modules must be undertaken to complete the programme, at which point successful participants receive the EAO Postgraduate Diploma in Implant-based Therapy.

Basics/ Theory Planning / Seminar Implant Surgery Restorative / Perio / DT

Sem 1 Posterior single unit; short & extended edentulous space; Low esthetic risk; sufficient bone volume History

Bone Physiology Osseointegration Dental Implant Surfaces Dental Implant Design Medical history / Systemic & Oral diseases How to prepare a case presentation Intraoral photography

Differential therapeutic considerations (Perio, Endodontics) Periodontal Status Bone Evaluation Minimum bone dimensions Soft tissue conditions Study casts Way up Surgical guides Case presentations

Preparation for surgery (Biosafety) Incision lines Drilling protocol Placement in relation to adjacent teeth Bone quality Primary stability Management of Complications Abutment connection

Prosthetic components Screw retained vs. cemented Occlusion in posterior implant borne restorations Interarch space Shaping of restorations Hygiene issues Maintenance Management of mechanical complications

Sem 2 Edentulous arches; Overdenture restoration on 2 and 4 implants

Changes of oral tissues in fully edentulous patients Biomechanics and implant positioning in edentulous jaws

Vertical & horizontal interarch relationship Bone & Soft tissue evaluation Wax up Surgical guides Case persentations

Use of mucosa & bone borne surgical guides Management of potential anatomical risks (mental foramen, sublingual grooves, sinus floor) Soft tissue management / Abutment connection

Overdenture treatment Bars, Clips, Locators Hygiene measures Maintenance Management of prosthodontic complications M

odul

e 1&

2St

raig

htfo

rwar

d (S

)


Sem 3 Posterior single unit; short & extended edent. space; full edentulism; Low esthetic risk; horizontal deficiencies; simultaneous grafting (GBR)

Defect classifications Biomaterials Barrier membranes

Defect history Bone & Soft tissue evaluation Study casts Wax up Surgical guides Case presentations

Incision lines Handling of biomaterials and barrier membranes Alveolar bone splitting Limited sinus lift lateral / transalveolar in conjunction with implant placement Soft tissue coverage Management of complications

Fixed bridge in edentulous patients Prosthodontic concepts on 6 – 8 implants Occlusion in fixed full arch restorations Hygiene aspects Maintenance Management of occlusal / mechanical complications

Sem 4 Esthetic Zone single unit; short & extended edentulous space; horizontal deficiencies; simultaneous grafting (GBR). Immediate placement with low esthetic risk

Esthetic conside-rations of dental restorations Socket healing Timing of implant placement after extraction Socket / ridge preservation

Profile / Lip line evaluation, Periodontal tissue evaluation 3D bone evaluation Study casts Wax up Surgical guides

Placement / vertical / horizontal position Incision lines Soft tissue management in areas of augmentation Management of complications Immediate placement in posterior areas with intact socket walls

Prosthodontic aspects in esthetic restorations No of implants Fixed Bridge vs. single crowns Occlusion in the esthetic zone M

odul

e 3&

4A

dvan

ced

(A)


Sem 5 Esthetic zone: Immediate placement, damaged wall/augmentation Immediate loading of single units, short /extended/edentulous cases

Preconditions for immediate loading Loading protocols Marginal bone / soft tissue reactions Soft tissue management

3 D planning Surgical guides Relevance of vertical / horizontal positioning CAD/CAM for immediate restoration

Implant placement in damaged sockets Simultaneous augmentation Soft tissue management and coverage Management of complications

Integration of immediate restorations Work flow and management Occlusal adjustments Provisional and definite restorations on immediately placed implants Maintenance Management of complications

Sem 6 Severe horizontal / vertical deficiencies: single unit; short & extended edentulous space; secondary implant placement after grafting

Anatomical changes due to atrophy in maxilla and mandible Harvesting areas for bone grafts Bone graft healing

Periodontal Evaluation Bone Evaluation 3D planning Soft tissue evaluation Interarch relationship Study casts Avoiding bone grafts (short implants, zygoma implants)

Incision lines / flap design

Recipient site preparation

Graft procurement and adaptation, graft fixation

Extended sinus floor augmentation

Soft tissue management and coverage

Management of complications

Removal of fixation screws

Secondary implant placement

Temporary implants

Vertical & horizontal dimensions of restorations Management of soft tissue problems Provisional restorations on temporary implants Prosthodontic concepts without grafting (short implants) Restorations on zygoma implants M

odul

e5&

6C

ompl

ex (C

)

Figure 9.1.1

Figure 9.1.2

Figure 9.1.3


How photography can improve your private practiceAntonello Appiani

The main goal of taking dental photographs is to document the different stages of treatment.

How to take photographs that are suitable for documentationEquipment and settings for inexperienced users:

� use a digital SLR camera (D-SLR) � work in ‘aperture priority’ mode � set the aperture value to F32 or higher � enable auto ISO � use a ring fl ash in auto fl ash mode � set white balance to 5,500K or fl ash mode � use an exposure speed of 1/60s � use manual focus for intraoral images and

autofocus for full-face pictures

Advanced equipment for experienced users:

� D-SLR Prosumer or Pro (D7100 or D610) � 50mm and 105mm macro lenses � twin fl ash and fl ash bracket

Advanced settings:

� use manual mode � aperture value of F32 or more � ISO 200 � fl ash manual mode with 1/1 of power � exposure time 1/125s � a ring fl ash is easy to use, but can make the image

lose its 3D quality. Twin fl ash is more expensive and heavier, but is also more creative and allows you to position the fl ashes parallel to the lens

Other elements to bear in mind when taking dental photographs:

� the use of black backgrounds is always highly recommended, especially in anterior areas, as the contrast highlights tooth translucency

� higher quality mirrors allow for higher levels of refl ection

� polarising fi lters help minimise refl ections

Why should we document treatment?1. Diagnosis and treatment planningPhotographs can help clinicians develop treatment plans. They can be analysed after the patient has gone and images can be enlarged to reveal fi ne detail. In orthodontic and prosthetic situations, for treatment in the aesthetic zone, photographs allow

you to analyse facial and oral frames by tracing reference lines and planes. This helps formulate the best treatment plan. However, the photographs must be taken with perfect symmetry and without positioning errors or perspective distortion in order for them to be usable.

2. Increased patient education and communicationUsing smile design software in conjunction with photographs can help the patient visualise treatment outcomes and make it easier for the practitioner to understand their treatment goals. Compared with traditional wax-ups, the possibilities provided by photography software are huge. Photographs of the try-in or mock-up can clarify the patient’s perception of the treatment plan, helping them express their wishes and make the best informed decision.

3. Communication with the laboratoryTreatment plans can also be shared with the laboratory technician who will use the additional information as a visual interpretation of the clinician’s ‘prescription’. This reduces the likelihood of confusion or miscommunication. ‘One picture is worth a thousand words.’ (Figures 9.2.1. and 9.2.2)

4. Legal documentationPhotographs can also help resolve disagreements between dentists and patients before a potential dispute reaches the litigation stage. We cannot rely on our memories alone to resolve patient complaints. Photographs can provide proof of the condition of the mouth before and after treatment, and are valid for use as forensic records. This provides legal protection for both the dentist and the patient.

5. Improving our practicePhotographs are also essential tools for case presentations, or as part of sharing and training programmes. During follow-up examinations, dental photography is very useful for studying the evolution of the case and evaluating treatment outcomes. It is a useful tool for providing feedback to learn from our own practice.

Dental photography can be used as a kind of ‘quality control’ measure. By enlarging and projecting photographs, any weaknesses in a treatment plan will also be magnifi ed, making them easier to identify. This helps us prevent potential mistakes and improve our future practice.



Private practice management and developmentSarah Chick-Richardson

Each patient who comes to our office presents a different case, and each case has its own challenges and scope for successful resolution. To know how to approach them, it is crucial to have detailed and personalised information. This is both a science and an art: the science is to provide patients with evidence-based treatments to the best of our ability; the art is to correctly apply appropriate protocols to individual patients. To this end we must employ a variety of skills: communication; patient advice; marketing; and so-called business intelligence.

CommunicationThere are three main questions we must ask:

� who is responsible for communication? � what needs to be communicated? � what is good communication and what is bad?

Almost everyone working in the clinic has the opportunity to communicate, whether they are dentists, auxiliaries, reception staff or members of the management team. The type of information that needs to be communicated depends on the situation. To achieve good communication the following should be observed:

� the flow of information must be managed appropriately

� channels of transmission should be taken into account

� the vocabulary should be selected accordingly, along with an awareness of who is delivering the information

� care must be taken to ensure that non-verbal communication is of a high standard too

‘People management’Recognising individual needs is the starting point when advising patients. We must be aware of our own training and limitations, and should be eager to meet the patient’s needs and keen to solve any problems. Finally we should be objective in our treatment planning, in deciding what the patient needs, and in estimating the value of the treatment.

MarketingThe success of a private practice depends on having a sound business plan and a marketing strategy that will promote its strengths.

When designing a treatment plan and its corresponding budget, we often have to balance patient expectations against what is available using evidence-based treatment. Information gathered by the patient prior to treatment is extremely important, and their expectations must therefore be tempered. On the other hand, when we ask patients what they want, it often comes down to a few simple things. Our proposals should be kept uncomplicated and be delivered in a clear and concise manner.

Word of mouth is the most powerful tool for promoting your practice, and it is how you can build a network of referrals. This can only be achieved by satisfied patients, and this is above all what we should strive for.

Business intelligenceBusiness intelligence, and being smart about how you manage your practice, will help you build a strong development strategy. To start, a few vital questions must be answered:

� where has each patient come from, and what was the source of the referral?

� how many new patients do you have and do you need?

� how many clinical hours do you and your team have available each year?

� how do you maximise the value of this time?

Depending on your answers to each question, a development strategy can be built that is tailored to the individual needs and characteristics of your clinic.

The patient journeyTo succeed in business, you must understand each type of patient and treat them accordingly. For returning patients, it is important to know what made them come back to the clinic and trust you again; their new needs must then be assessed. For new patients, you should find out what brought them to the clinic (for instance an advert; a publicity campaign; or word of mouth). This information should be recorded and can be used later to further enrich that source of new patients.


How to avoid the carpenter’s approach to implants

A number of clinical reports have been published on immediate loading since the 1990s. Over the last two decades, positive outcomes for immediate implant restorations – removable or fixed – have been supported by a large body of evidence in virtually all clinical situations. This has led to a trend towards increasing primary mechanical stability above the previously recommended levels. As a result, clinicians now generally prefer a higher insertion torque, without taking into account its biological impact on living bone.

The influence of insertion torque on primary stability, implant survival and marginal bone lossMichael Norton

Primary stability is the big issueIn early and immediate provisionalisation/loading, primary implant stability is one of the most important factors for ensuring safety and predictability. But how much primary stability is needed?

Primary stability results from a mechanical connection between an implant and the surrounding bone. The way in which the implant and bone interlock with each other reduces micromotion and shear forces at the interface while transferring forces to the bone. This mechanical stiffness is typically measured as rotational friction and registered as insertion torque.

Factors that can influence primary stability are:

� implant design (geometry; thread profile; interfacial design; surface preparation)

� bone density (especially cortical thickness) � surgical protocol (osteotomy preparation)

There are several methods for evaluating primary stability:

� tactile perception, although results are subjective and difficult to quantify, due to variation between operators

� Periotest, involving an evaluation of micromotion; it is similarly unreliable

Two methods which are increasingly being used are:

� peak insertion torque (PIT) � resonance frequency analysis (RFA)

Are PIT and RFA different?Both methods assess different aspects of stability, and could even be said to complement one another. While PIT measures the resistance of shear forces or rotational stability registered in Ncm, RFA measures the axial stiffness of the implant – the resistance to lateral micromovement – and is registered as an implant stability quotient (ISQ) (Figure 10.1.1).

This may be why most studies have discovered little or no correlation between PIT and ISQ values1. Furthermore, it has been shown that PIT is unreliable for predicting implant failure. By contrast, ISQ has been seen to predict implant success: higher ISQ values at implant placement have been observed in successful implants2. In a cadaver study, a significant correlation between insertion torque and bone density has been found, but no correlation between insertion torque and ISQ3.

How much insertion torque is needed?The speaker has published a study on immediately placed and restored single-tooth implants. In it, he concludes that an insertion torque of 10–25Ncm – lower than is generally recommended – can yield favourable survival rates, while optimising the maintenance of marginal bone levels4 (Figure 10.1.2). In a clinical study on immediate rehabilitation of the edentulous maxilla, the overall cumulative implant

1 Degidi et al. Clin Implant Dent Rel Res 2012; Gonzalez-Garcia et al. Med Oral 2011; Barewald et al. IJOMI 2012; Vianna dos Santos et al. Clin Implant Dent Rel Res 2009

2 Al-Nawas et al. IJOMI 20063 Boustany et al. IJOMI 20154 Norton MR. IJOMI 2011


survival rate was 96%, even though 38% of the implants had an insertion torque of 10–20Ncm5.

A recent clinical study involved 59 immediately placed implants with an ISQ ≤ 69 and different insertion torques (20–50Ncm). 100% of the implants achieved a good outcome, illustrating that a low insertion torque may not be a factor for predictable success in immediately placed implants6. Although there is still no consensus regarding the optimal insertion torque value for loading implants, this value is now trending downwards.

Implant design must also be taken into account, as primary stability is partially system-dependent. Additionally, the maintenance of implant stability during the post-surgical healing period is of the utmost importance to allow primary stability to become secondary stability.

By contrast, some authors argue that high insertion torques can damage interfacial bone and produce

5 Toljanic et al. IJOMI 20096 Levin BP. Int J Period Res Dent 2016

micro-cracks, due to increased bone strain and excessive bone compression. Micro-cracks can trigger further bone remodelling, and may delay osseointegration or result in increased marginal bone loss7. This hypothesis has not been confi rmed by other studies8.

From insertion torque to ‘viable constraint’ (vC)‘Viable constraint’ is a concept which combines both values of stability (PIT and ISQ) and considers the critical pressure on bone. It may prove preferable to insertion torque. Several clinical studies have demonstrated that 25Ncm is suffi cient for immediate loading protocols. It is therefore recommended that viable constraint is set at PIT = 20–25Ncm and ISQ = 60. If one value falls below these thresholds, it can be counter-balanced by the other. For example, an implant with a PIT = 15Ncm and ISQ >65 may still be safe for immediate loading (Figure 10.1.3).

7 Duyck et al. COIR 2015 ; Trisi et al. IJOMI 2011; Cha et al. J Dent Res 2015; Barone et al. Clin Implant dent Rel Res 2015

8 Li et al. IJOMI 2015; De Sanctis et al. IJOMI 2016

How should implant stability be assessed?

RFA measures resistance to lateral micro movement

Torque measures resistance to shear forces

Micro movement could jeopardize the treatment outcome

The Influence of Insertion Torque on Implant Survival in Immediately Placed and Restored Single-tooth ImplantsNorton MR. JOMI 2011; 26: 1333-43.

61 PatientsMean Age: 54 years68 implants95.5% ISR up to 9.5y in function

It can be concluded that immediate temporization of single-tooth implants placed with a low insertion torque (10 -25Ncm) can yield favorable survival rates with optimized maintenance of marginal bone levels compared to the generally accepted norm.

D

H

Surface Area of implant in contact with cortical bone = H * π * D

P = Critical pressure on bone

Therefore Critical total pressure against the implant = P * H * π * D

μ = coefficient of friction therefore total force resisting rotation = μ * P * H * π * D

Lever = D/2

Resisting Torque = μ * P * H * π * D2

2

H

What Governs Insertion Torque?

What Governs Critical Pressure?

Figure 10.1.1

Figure 10.1.3

Figure 10.1.2


Evidence-based implant carpentry. What are you using, what are we doing?Ryo Jimbo

When using the analogy of carpentry, we must distinguish the good carpenter from the bad. As Norton explained in a recent IJOMI editorial, primary stability is not the same as insertion torque9. Further, mechanical stability is not the only aspect that must be considered (Figure 10.2.1). It is important to support the shift from primary stability (highly dependent on macro-geometry and instrumentation), to secondary stability (achieved by the deposition of new bone on the implant surface). The bad carpenter’s approach compromises this biological process, and must be avoided.

Primary stability depends on three factors:

9 Norton MR. IJOMI 2013, editorial

� bone quality and anatomical morphology: both are relevant in determining insertion torque values10

� macro-design: insertion torque is specifi c to implant design (Figure 10.2.2); there are differences in short-pitch and healing chamber macro-design types11, the latter show lower torque but good stability

� surgical approach: the drilling protocol should be adapted to the bone composition12

In conclusion, a good clinician must understand and measure primary stability, managing the tools available in order to achieve it, and combining clinical experience with evidence (Figure 10.2.3). A good clinician is a good carpenter and a good scientist.

10 Lindhe et al. COIR 2012; Stanford et al. IJOMI 201611 Coelho & Jimbo. Arch Biochem Biophys 201412 Jimbo et al. Int J Oral Maxillofac Surg 2014; Stocchero

IJOMI 2016

But that’s not all

Biology kicks in

Implant stability can part be explained by this:

Insertion torque is implant design specific and does notalways correlate to adequate primary stability.

Implant design and implant stability

Primary stability is obtained by numerous factors!

Figure 10.2.1

Figure 10.2.3

Figure 10.2.2


Bone versus implants! Do we need to grant the biomechanical to the biological? The orthopaedist’s perspectiveThierry Joudet

The answer is yes!Bone is an important organ and performs essential physiological functions, providing:

� mechanical support � mineral homeostasis (phosphocalcic metabolism) � a location for haematopoiesis � endocrine function

Bone has an anisotropic morphology with two basic types:

1. Cortical bone, which is compact and characteristically stiff, with a Haversian structure and porosity less than 30%

2. Cancellous (also known as trabecular or ‘spongy’) bone, with a porosity ranging from 30 to 90% and a higher vitality and biological reactivity

Factors relating to bone formation and repair include:

� it takes place in four locations (medullary canal, cortex, periosteum, soft tissue)

� it involves two kinds of consolidation (primary bone healing, which involves direct Haversian remodelling by the cortex itself; and secondary repair involving responses in the periosteum and external soft tissues)

� it features two types of ossifi cation (intramembranous and endochondral)

� it is characterised by fi ve stages (haematoma, infl ammation, angiogenesis, cartilage formation and calcifi cation, remodelling)

Bone is capable of self-repair (in cases of fractures, micro-fractures, and micro-cracks) via processes of modelling and remodelling. These processes are based on basic multicellular units (BMUs), which

respond directionally to mechanical loads. Stem cells are precursors to osteoblasts. They are attracted to the site of bone formation and differentiate into osteoblasts according to signals released by osteoclasts. This makes up a system of feedback between the two cells (Figure 10.3.1).

Osseointegration at implant surfaces is governed by cytokines. It takes time – about three months

– for the process to achieve mechanical stability through maturation and mineralisation to become lamellar bone. After surgical trauma, bone tissue must remodel itself in close contact with the implant walls. This involves a delicate balance between surgical technique, biological environment and implant design, which must be achieved to ensure success. Excessive infl ammation, cytotoxicity and activation of the complement system are potential dangers. If the balance tilts towards biocompatibility, the process can be regarded as bio-tolerance, bio-inertia or bio-activity. This, in turn, stimulates in consecutive order osteoconduction, osteoinduction and fi nally osteogenesis. Implant surfaces must be engineered with suffi cient porosity at macro, micro and nano levels. In the future, surfaces may be biologically confi gured by stem cells or BMPs (bone morphogenetic proteins) (Figure 10.3.2).

The speaker fi nished his presentation with a review of the evolution of orthopaedic implants from 1893 to the present day, through the astonishing history of the Joudet family. Different biomechanical designs have been developed for over a century to deal with stress shielding, wear and unsealing of prostheses. The most recent designs are smaller, allowing for less invasive surgical installation. They feature surface treatments that are designed to stimulate inductive support for the desired biological outcome (Figure 10.3.3).

SFA 2012 D. Chappard® Figure 10.3.1 SFA 2012

future

2 waysMake inductive a support

Stems cells

B.M.P.

Figure 10.3.2

SFA 2012Figure 10.3.3

Courtesy of Mathys®


Emerging technologies: head-to-headNew materials and technologies are constantly being developed, but it takes time to build a body of clinical evidence following preclinical and experimental evaluations. Until this emerges, clinicians are in a no man’s land where opinions and experiences are exchanged, and opposing viewpoints are discussed. In this session three different and currently hotly debated procedures and technologies were discussed.

Hand guided surgery versus guided surgeryDaniel Wismeijer

Where we are currently: trying to get the prosthesis to fitDigital workflows are still imprecise and less accurate than we would like them to be. Deviations between the planned implant position and the final position that is achieved by guided surgery are inevitable1.

A recent systematic review and meta-analysis has assessed the deviations recorded in 24 studies involving computer-assisted surgery. The results showed the following deviations:

� mean 1.12mm (maximum 4.5 mm) at the entry point

� 1.39mm (maximum 7.1mm) at the apical location � 3.9º mean axial deviation (maximum 21.2º)

Complications were reported in 36.4% of cases, including:

� template fractures during surgery � unexpected changes in the surgical plan � insufficient primary implant stability achieved � additional grafting required � problems relating to poorly fitting prostheses

(screw loosening or prosthesis fracture)

The study reported no differences that were statistically significant between:

1 Throughout this presentation, guided surgery refers to static guided surgery, not dynamic navigation

� the maxilla vs. the mandible � fully edentulous vs. partially edentulous patients � the study design (cadaver, model or clinical) � guide production method

Significantly larger deviations were revealed in the P-values documented in tooth-supported guides vs. bone-supported guides. The latter were associated with greater deviations. Further, it seems that flapless approaches proved more accurate, but this may be due to the use of bone-supported guides when a flap was raised. Finally, fully guided implant insertion was found to be more precise than free-hand insertion2.

Instrument inaccuracy (Figure 11.1.1)CBCT scanning has its own inherent inaccuracies. Multiple factors may influence deviations even within the same device, such as field of view (FoV) selection; voxel size; radiation parameters; patient anatomy and positioning; patient movement during exposure; and segmentation threshold for reconstruction3.

On the other hand, there can also be dimensional errors in the data obtained from intraoral scanners. As the distance between bodies being scanned increases, the precision of intraoral scanners decreases, unlike with lab scanners. Thus deviations have been found when surface scan models and the same models derived from CBCT data are

2 Jung et al. IJOMI 2009; Tahmaseb et al. IJOMI 20143 Hasan et al. Clin Oral Investig 2010


superimposed4 (Figure 11.1.3). The fabrication of drilling templates and drill tolerances are additional factors that may cause deviations.

In this situation, could there be advantages to using hand-guided surgery?Foregoing surgical guides has its obvious advantages, especially when compared with errors that can arise when using ‘hand-brain’ surgical guidance. Some errors may present as postoperative complications, or later during the restorative phase. Most can be prevented by careful planning.

4 van der Meer et al. PLoS-ONE 2012; Flü gge et al. COIR 2016

There is a need for an evidence-based evaluation of clinical indications to balance treatment accuracy against associated risks and help us decide whether the additional cost and effort of computer-assisted surgery is worth it.

Software is ubiquitous in all areas of technology, but can also be a ‘weapon of mass deceit’ because it discourages clinicians from doing the thinking for themselves (Figure 11.1.5). Currently, there is still insuffi cient evidence to demonstrate that computer-assisted surgery is systematically superior to conventional procedures in terms of safety, outcome, morbidity, or effi ciency.

Instrument accuracy

1

CBCT scans Intra oral scans Repositioning The drills The drill guide The software

Accuracy assessment

Tabea Flugge 2015-2016 ITI scholar at ACTA

Deviations between surface scan models after registration with CBCT model

Why Software is eating the world Marc Andreessen 2011

Michiel van Genuchten & Les Hatton. When software crosses a line. IEEE software Jan/Feb 2016:29-31

00101110001001000111101010101011100101010001111010100111001001111001010001110011000111101110100111111111000000101101010101010101011000100111110000q101010000000000000001111111111111010101010101010101010101010101010101011

But: Software can be turned into a weapon of mass deceit very cheaply

Figure 11.1.1

Figure 11.1.3

Figure 11.1.5

Figure 11.1.2

Figure 11.1.4


Autogenous bone blocks versus allogeneic bone blocksZvi Artzi

Autogenous bone blocks are still considered to be the gold standard. Augmentation using autogenous bone blocks increases 3D volume by up to 4.3mm horizontally and 4.7mm vertically. This is an improvement of about 30% compared with GBR procedures5. The advantages of using autogenous bone blocks are:

� perfect biocompatibility � no antigenicity � bone inductive properties

A recent study involving autogenous bone blocks measured mean bone-implant contact at 42.34%, and new bone formation at 68.32%6. Although it is still the subject of debate, a healing period is recommended before placing implants. Both experimental and human histological studies have reported that increased bone-implant contact can be obtained using a staged approach. Studies have also documented higher stability measured by ISQ and lower marginal bone loss7.

It has yet to be assessed what percentage of the block remains vital and for how long while revascularisation takes place. During this process, a substantial amount of resorption has been recorded

5 Milinkovic & Cordaro Int J Oral Maxillofac Surg 20146 Rocchietta et al. Clin Implant Dent Rel Res 20157 Rasmusson et al. Int J Oral Maxillofac Surg 1998, 1999;

Lundgren et al. Int J Oral Maxillofac Surg 1999; Faria et al. Int J Oral Maxillofac Surg 2010; Sanz-Sanchez et al. J Dent Res 2015; Artzi et al. IJOMI 2016

(up to 60%), and there is currently no way of preventing this. To compensate for these levels of resorption, the use of resorbable collagen membranes and anorganic bovine bone has been proposed8. Another solution may be the use of bone decortication to enhance angiogenesis from bone marrow, but this has not yet been conclusively proven9.

The most common complications that can arise include mucosal dehiscence, along with bone graft or membrane exposure, and complete failure of bone block grafts and neurosensory alterations. Exposures occurred more frequently in vertical than in horizontal augmentations. A recent systematic review reported complete graft failure in 8–20% of the cases10.

With regard to donor site morbidity, altered sensation was measured in 62% of cases following surgery, when the block was removed from the symphysis. Thus patient morbidity; the frequency of postoperative complications; and the technical skill required for the procedure are all important concerns.

Can allogeneic blocks serve as an appropriate alternative treatment?The view that allogeneic bone blocks can enhance ridge volume in a similar way to autogenous blocks, and without the associated mass reduction, is gaining momentum. Indeed, allogeneic bone blocks present some obvious advantages:

8 Sanz-Sanchez et al. J Dent Res 20159 Verdugo et al. Clin Implant Dent Rel Res 201210 Milinkovic & Cordaro Int J Oral Maxillofac Surg 2014

At 6 months

ZA

Allogenic bone block Xenogenic particlesUpon Re-entry –• A mush-like appearance. The cortical ridge envelope has not been established• A “softy” osseous table. The fixation screw-heads surrounded by soft tissue

Marked vertical ridge resorption• Poor vitality• Empty lacunae• Poor vascularization• High resorption• High CT fraction• Low resistance to drilling• High rate of spontaneous exposure• Quality/Quantity of Osseointegration?? ZA



� the surgical procedure is shorter and simpler � there is less morbidity � there are fewer associated postoperative

complications � treatment acceptance is generally better among

patients and surgeons

Allogeneic blocks come in several forms, each with their own characteristics. Cortical plates have a slow remodelling rate, whereas cancellous blocks exhibit less structural strength and have a higher rate of revascularisation. Cortico-cancellous blocks offer a mixture of both characteristics, with the thin outer cortical portion maintaining initial stability, and the inner cancellous part providing increased osteoconduction. There is no solid evidence, however, to prove that true osseointegration occurs between allograft blocks and implants.

Following an overview of the current literature, it can be concluded that there is insuffi cient scientifi c evidence to support the use of allograft blocks in generalised clinical situations. The systematic

reviews11 mainly identifi ed observational studies, most of which report good graft incorporation and implant survival in the short-term. By contrast, a recent study found that wound dehiscence occurred in 77.8% of cases. Another study in 2016 had to be cancelled due to the high rate of complications12.

It has been documented – although with some variability – that only 8.4% of cases resulted in the formation of new bone, and about 50% in the formation necrotic bone. Some studies have reported poor graft incorporation and marked resorption over time, along with a higher incidence of graft exposure, and partial or total loss of the graft in some cases13 (Figures 11.2.1 and 11.2.2).

The speaker concluded with a table illustrating the outcomes associated with the various types of bone blocks (Figure 11.2.4).

11 Waasdorp & Reynolds IJOMI 2010; Monje et al. J Biomed Res Int 2014

12 Leong et al. Implant dent 2015; Draenert et al. Oral Surg Oral Med Oral Pathol Oral Radiol 2016, respectively

13 Spin-Neto et al. COIR 2014, 2015; Chiapasco et al. IJOMI 2015

Bone–implant contact and new bone formation within human freeze-dried bone (FDB) blocks grafted over rabbit calvaria Z Artzi et al Int J of Oral & Maxillofac Impl 2017 (accepted)Methods:• 18 rectangular FDB blocks were stabilized bilaterally to 9 rabbit calvaria (a pair each).• 18 (5.0X6.0 mm ) implants , 9 - immediate placement (IP) and 9 - delayed placement (DP) at 3 months. Results At 6 months :• Mean BIC: IP implants - 10.50% ± 5.99; DP implants - 23.06% ± 9.58 (P<0.001).• NBF was observed primarily in the cancellous zone of the block adjacent to the calvaria. • The extent of NBF into the block was only around 11% for the two groups.

IP implants

DP implants

ZA

Alveolar ridge augmentation by

Particulate graft/Mem (GBR) Autogenous Blocks Allogeneic blocks

Volume outcome/NBF ☺☺☺ /☺☺☺ ☺☺☺ / ☺☺ ☺?? / ??☺Fully Remodeling /

Revitalization ☺☺☺☺ *☺ ?? ????** ,*

Osseointegration (BIC) ☺☺☺☺ ☺☺☺☺ **☺ ??

Morbidity / Complications ***?☺☺ ☺☺?? ☺??†

At this stage……

☺☺☺☺ - very happy☺☺ - pleased☺☺?? - inconclusive/some drawbacks☺?? - well….some major concerns….???? - YOU TELL ME!

*

* Spin-Neto et al 2014 (27.6% AuCCB vitality; 8.4% AlloBB vitality)** Artzi et al 2016 (11% AlloBB vitality; 23% osseointegration)*** Milinkovic & Cordaro 2014 (6-8% for AuCCB, 12-13% for GBR )† Chiapasco M et al 2015; Draenert FG et al 2016



Connective tissue graft versus soft tissue substitute around implantsGiovanni Zucchelli

Recession of the buccal soft tissue margin around dental implants is a common complication which leads to elongation of the clinical crown, or metallic components becoming visible in the aesthetic zone. In the majority of cases, this is caused by poor positioning of the implant, resulting from the implant platform having been placed too buccally and/or apically.

It has been demonstrated that soft tissue plastic surgery procedures can be successfully used to correct soft tissue recession in conjunction with pre- and post-surgical prosthetic approaches14. This treatment aims to relocate the soft tissue margin and takes approximately one year:

� there is an initial 2-month phase of soft tissue maturation and creeping. The implant-supported crown is removed and replaced with a shorter one. There should be no contact with the soft tissue, and the abutment diameter should be reduced by as much as possible

� once the soft tissue has grown to form papillae, the surgery can be performed using a coronally advanced fl ap combined with a connective tissue graft (CTG) deriving from the de-epithelialisation of a free gingival graft

� after the tissue has healed there is a second maturation phase of 4 months followed by a second conditioning phase. A new screw-retained provisional is fi tted to put apical pressure on the zenith area and allow the papillae to fi ll the proximal spaces

� fi nally, the defi nitive abutment and restoration can be placed (Figures 11.3.1–11.3.3)

14 Zucchelli et al. COIR 2013; Roccuzzo et al. COIR 2014; Le B et al. JOMSurg 2016; Zucchelli et al. submitted

Can similar outcomes be achieved with soft tissue substitutes?The speaker described how he had recently reviewed various surgical procedures whose goal was to increase keratinised tissue width, comparing apically positioned fl ap procedures with vestibuloplasty. He also compared different methods for autogenous soft tissue grafting (free gingival graft or connective tissue graft) versus methods that used biomaterials (acellular dermal matrices and collagen matrices). He found six clinical studies, three of which were RCTs. Soft tissue substitutes failed to produce better results in any of the studies, but favourable results were achieved using autogenous soft tissue in two studies. The other four reported similar outcomes. He concluded that free gingival grafts remain the gold standard, while collagen matrices reduce post-operative morbidity and surgical times, as well as achieving a better aesthetic outcome.

ConclusionsA peri-implant soft tissue margin about 2mm thick is required to ensure long-term stability. Currently, augmenting the thickness of the buccal soft tissue using CTG combined with a coronally advanced fl ap is a reliable procedure. It is crucial that suffi cient papillae are available to de-epithelise, and that the fl ap is sutured coronally in order to achieve a good result. No risk of subsequent shrinkage has been observed, but rather a tendency for creeping. Although there is evidence to suggest that biomaterials are becoming a more reliable option than they were previously, it is advisable to use them in more straightforward cases, such as mucogingival surgery with teeth, but not in cases involving implants.

Zucchelli et al. A novel surgical-prosthetic approach for soft tissue dehiscence coverage around single

implant. COIR 2012

- increase the volume of the interprosimal soft tissue

Key factors for for soft tissue dehiscence coverage around single implant

- CTG positioning

- CTG thickness and quality?

- Full coverage of CTG by CAF

3

Figure 11.3.1

Figure 11.3.3

Figure 11.3.2


Optimal long-term results for osseointegrated implants

Japan, as the invited country at the 2016 congress, presented a session delving into two interesting fields: bone augmentation and mechanobiology.

A new strategy for bone augmentationShohei Kasugai

The current status quoHaving enough bone around an implant is a prerequisite for long-term success. However, bone volume is often insufficient, making augmentation procedures necessary. Autologous bone grafts are still considered the gold standard, but the procedure is limited by the amount of harvestable bone available and associated with high patient morbidity. On the other hand, bone substitutes are less effective since they are only scaffolds and lack cells and signal molecules.

Tissue engineeringThe current strategy for resolving this challenge is tissue engineering. This involves three key players: stem cells, signal molecules and an appropriate scaffold. These biological materials are combined exogenously in order to create functional tissue to facilitate regeneration.

Different types of stem cells have regenerative potential:

� embryonic � induced pluripotent � stimulus-triggered acquisition of pluripotency

cells (STAP) � mesenchymal

These cells work in conjunction with signal molecules – BMPs, PDGFs, FGFs, TGFs, VEGFs – and create new tissue within a scaffold structure which can be made out of collagen; fibrin; bone substitutes; or biodegradable polymers. The aim of tissue engineering is to apply these combinations in situ and biologically stimulate bone regeneration, achieving similar results to autogenous grafts.

Recent experiments involving signal molecules – such as PDGF and BMP-2 – or stem cells have found

that they can be effective for bone augmentation. However, this procedure is not currently available in daily practice due to its complexity and cost.

A new membrane in developmentA new synthetic GBR membrane is under development, made of a cholesterol-bearing pullulan (CHP) polysaccharide-nanogel. The membrane is cross-linked, and is capable of trapping both hydrophobic and hydrophilic molecules inside itself. Since CHP-nanogel is composed mostly of water (over 90%), the membrane can absorb endogenous growth factors secreted by tissues, exchanging them for water, and later release them to enhance bone regeneration. A study has demonstrated that the new CHP-nanogel membrane could store PDGF signalling molecules, and achieved better outcomes than traditional collagen membranes1.

In addition to growth factors, the new membrane can also incorporate small, biologically active molecules. For example, another study has shown that a CHP-nanogel membrane treated with prostaglandin E1improved the wound healing process2.

Is regeneration possible without graft materials?A widely reported study has shown that space maintenance alone is enough for effective bone augmentation. The study also showed that scaffolds using xenograft materials alone were more effective than autologous bone3.

Furthermore, in some cases sinus membrane elevation can be achieved without the use of graft material. Another clinical study has concluded

1 Miyahara et al. J Tissue Eng Regen Med 2012; Maeda et al. J Biomed Mater Res B Appl Biomater 2015

2 Kobayashi et al. J Biomed Mater Res B Appl Biomater 2009

3 Aghaloo & Moy IJOMI 2007


that graftless sinus augmentation can be a reliable technique, provided that space for bone formation is maintained4. The space created below the Schneiderian membrane provides a favourable four-wall defect.

The expandable E-GBR conceptIn animal experiments, it has been discovered that periosteal elevation can encourage bone growth from the basal bone. This phenomenon is based on the same mechanism as Ilizarov’s principle of osseous distraction. Lifting the periosteum to

4 Lundgren et al. Clin Implant Dent Rel Res 2004

stimulate bone formation under the barrier may open up new channels of vertical bone augmentation. Preliminary results from the experiment report an increase of about one third of a millimetre per day following elevation of the periosteum5.

This new direction in regenerative treatment is mainly based on the healing potential of bone. Instead of applying exogenous factors, which is the focus of the majority of current tissue engineering strategies, in this method bone is augmented solely by providing space.

5 Zakaria et al. J Tissue Eng 2012

An analysis of dental implant treatment based on biomechanics and mechanobiologyKeiichi Sasaki

Why should we focus on force?Biomechanics concerns the effect mechanical forces have on biological tissues (Figure 12.2.1). Mechanical forces can cause stress in peri-implant tissues, with the amount of stress determined by bone morphology and density, as well as by loading technique. Excessive stress can produce tissue reactions including: inflammation; bone resorption; tissue and implant deformation; and bone remodelling.

One of the principles of mechanobiology is that these reactions stem from cellular processes such as differentiation; proliferation; and apoptosis, and are regulated by signals to cells which are generated by mechanical loading. Together they make up an active and adaptive response to environmental biophysical stimuli.

Although evidence is scarce, it is widely believed that high levels of mechanical stress – and the micro-cracks and micro-damage that can be caused by them – hinder bone homeostasis. This can lead to inflammation and bone resorption around the implants.

Evaluating force on implantsFew studies have been carried out to measure in vivo forces received by implants. Those that have been conducted generally used strain gauges, devices which are unsuitable for capturing the complex vectors associated with 3D forces. It is important to measure forces transmitted in 3D since the finite element analysis (FEA) software used to simulate force and its impact requires data that is as comprehensive and accurate as possible.

The authors of one study used a 3D piezoelectric force sensor to measure the magnitude and direction of functional forces of a tooth in vivo6. It was then possible to measure the 3D force on the implant and include it among the data uploaded to the patient’s

6 Kawaguchi et al. J Biomech 2007

FEA. This meant that the stress distribution around peri-implant tissues could be truly evaluated. It was concluded that7:

� lower stress levels were reported in the peri-implant bone of the splinted model than in the non-splinted model

� the model with four implants had favourable stress distribution and lower intensity than the system supported by two implants

� high stress levels were found around tilted distal implants and where thin cortical bone was present

� the results favoured the mechanical stability achieved by using more implants, and reinforced the benefits of using biological data-based FEA (Figure 12.2.2)

In a cantilevered fixed partial denture, the extended finite element method (XFEM) showed high stress and strain concentration around the implant near the cantilever side, which could increase the risk of mechanical failure8 (Figure 12.2.3).

Mechanobiological reactionsModerate mechanical stress is required to maintain metabolic balance in osteogenic-dominant bone remodelling. However, the precise mechanotransduction mechanism that triggers the anabolic reaction of osteoblasts has not been defined in experiments. Consequently, the molecular differences between moderate and excessive mechanical stress are largely unknown.

Using a cell stretch system (ST-140 Strex), the sequence of signalling molecules elicited by mechanical stimuli on the cultured osteoblasts could be observed. It was found that lower levels of stress contributed to osteoblast differentiation, whereas higher levels caused cell apoptosis. Using RNA interference screening, it was possible to determine which intracellular signalling pathways were activated during osteogenesis, and which

7 Shigemitsu et al. Odontology 2012; Shigemitsu et al. Comput Biol Med 2014

8 Zhang et al. App Mech Biomat 2016; Yoda et al. J Oral Rehab 2016


played a role in protecting against mechanical stretch-induced apoptosis9.

The relationship between bone metabolism and loadingThe speaker offered some insights into bone metabolism dynamics using bone scintigraphy with radionuclides and positron emission tomography-computed tomography (PET-CT) scanning.

An experimental study using bone scintigraphy has documented the changes that occur in bone metabolism around implants under mechanical stress. Two implants were inserted in medial proximal tibiae of rats, and load was applied using closed-coil springs with 0.5 to 4.0Ncm. It was concluded that bone metabolism around the implants increased with loading, depending on magnitude and duration10.

9 Fukuno et al. Biochem Biophys Res Commun 2011; Matsui et al. J Biol Chem 2014; Zhang et al. Biochem Biophys Res Commun 2016

10 Sasaki et al IJOMI 2008

Using the same animal model, and also using bone scintigraphy, another study examined the effects of early and immediate loading on bone metabolism. Initially, bone metabolism increased during wound healing and then gradually decreased, returning to its baseline value regardless of load timing. But the increases in bone metabolic activity differed depending on when the implant was loaded: later load applications were found to be associated with higher bone metabolism11.

Finally, an 18F-fl uoride PET-CT was used to evaluate bone metabolism in the residual mandibular ridges of three patients who were wearing free-end removable partial dentures. The study recorded an initial metabolic increase in bone beneath the denture, followed by a decrease after about three months. No bone structural changes were detected by clinical X-rays. It seems that bone metabolism is related to pressure caused by removable prostheses, but a metabolic balance is reached after an initial reaction. This suggests that bone remodelling involves a kind of metabolic equilibrium12.

11 Yamamoto et al. COIR 201412 Suenaga et al. Ann Nucl Med 2012

Organs (Teeth/Alveolar Ridge/TMJ）

Tissues (Bone/Cartilage/Mucosa/

Connective Tissue）

Cell

Signal Transduction in Cell

Power Source (Jaw Muscles)

Dental Prostheses

Force Transduction

Stress Transduction and Strain Expression

Signal Transduction by Mechanical Stress

Force/Stress Transduction

Receptive Mechanism of Mechanical Stress

Cell Reaction by Mechanical Stress

Mechanobiological Reaction

Tissue Reaction by Mechanical Stress

Strain Expression

Biomechanics

Mechanobiology

Dental ProsthesesDental ProsthesesDental Prostheses

Link of Mechanical Stress–Mechanobiological Reaction in Stomatognathic System : Based on the concept of Physiome

1 1

４ implants supported

２ implants supported

Implant Supported Denture

Clips

Measurement of ３D Load on Implants supporting OD

Solid Line : 4 implant supported Dotted Line : 2 implant supported

Bar Attachment

3D Transducer

Jig for Sensor

Titanium Screw

Frontal Sagittal

50N

Average Loads Vectors during MVC

2

The University of Sydney Page 3

FEA for 3-unit implant-supported FPD Collaboration with Univ. Sydney, Bioengineering

3iFPD 2iFPD

2idcFPD 2imcFPD

J Oral Rehabil. 2016

J Prosthodont Res. 2016

Figure 12.2.1

Figure 12.2.3

Figure 12.2.2


Implantology needs periodontologyThis session was hosted by the Société Française de Parodontologie et d’Implantologie Orale (SFPIO), the scientific society with whom the EAO collaborated for the 25th annual meeting.

Periodontal plastic surgery to prevent biological complications in the aesthetic zoneCaroline Fouque

Periodontal plastic surgery has been defined as the ‘surgical procedures performed to correct or eliminate anatomical, developmental, or traumatic deformities of the gingiva or alveolar mucosa’1.

Biological complications can become aesthetic complicationsThe aesthetic outcome of implant restorations is highly dependent on the characteristics of the peri-implant mucosa. These, in turn, are affected by biological complications. This is important, as peri-implantitis may arise in one in five patients. The incidence of the condition is reported in 10% of implants and 20% of patients2. A 5-year meta-analysis found that peri-implant mucosal recession occurred in 7.1% of cases3.

It was recently stated that ‘the sooner the recession arises, the bigger our responsibility is’4. This refers to the fact that early recession is generally caused by poor implant positioning or mishandling of the soft tissue, while later recession may be a consequence of biological complications involving more patient-related factors (Figure 13.1.1).

A clinical study of patients’ subjective perception of mucosal recession found that although the number of recessions was large in some instances, few were actually perceived by the patient (28%). Of these, only a quarter represented an aesthetic concern for which the patient requested treatment5. This was due mainly to visibility, and was determined by the patient’s smile line type. In a multicentre study, it was concluded that assessments of gingival visibility

1 Wennström An Periodontol 19962 Klinge & Meyle The Third EAO Consensus Conference.

COIR 20123 Jung et al. COIR 20124 Roccuzzo SFPIO Congress Lecture, Lyon 20165 Nieri et al. J Clin Periodontol 2013

should be performed during forced smiling rather than natural smiling6.

Does tissue around implants and teeth have the same risk of recession?Significant changes can occur in soft tissue levels following implant therapy. A 2-year clinical study of 106 implants in 39 patients found apical displacement of the peri-implant soft tissue margin of up to 1mm or more in 60% of cases7.

Thin gingival biotypes are recognised factors influencing buccal recession in both teeth and implants. A direct correlation has been documented between thicker gingival tissues and greater peri-implant mucosal dimensions. However, the effect of gingival thickness on peri-implant tissue response is limited to facial gingival recession, and does not influence interproximal papillae or proximal marginal bone levels8.

In a recent clinical study evaluating gingival thickness in 336 patients, more than two thirds of male patients were found to have thick gingiva, whereas the majority of female patients had thin gingiva. Further, it was observed that gingival biotypes in females could vary with age, unlike in males9.

Recession may be due to the remodelling that takes place after implant surgery. This process is associated with a reduction in bone volume, especially in bone facial height and thickness. As a result, the mucosal margin may be apically displaced10.

A prospective clinical trial comparing thick tissues and thin tissues alone, and thin tissues thickened with allogenic membrane, found that thin

6 Liébart et al. Perio 20047 Oates et al. Implant Dent 20028 Kan et al. J Periodontol 2003; Kan et al IJOMI 20119 Manjunath et al. J Clin Diagn Res 201510 Cardaropoli et al. COIR 2006


peri-implant tissues were associated with early bone loss11. Regardless of statistical incidence, however, a careful examination of the biotype should be conducted, and tissue modification considered, when developing a treatment plan.

Do implant procedures increase aesthetic risks?Following immediate implant restoration, mean buccal marginal mucosal recession of 1mm was observed in 40.5% of implant sites; only 14.3% exhibited no recession. In addition to tissue biotype, implants with a buccal position demonstrated three times more recession than implants with a lingual position12 (Figure 13.1.2). Proper implant positioning is perhaps the main factor in preventing soft tissue aesthetic problems.

Do we need keratinised mucosa around implants to prevent inflammation?The width of keratinised mucosa (KM) is defined as the distance between the mucogingival junction and the free gingival or mucosal margin. Whether a minimum KM dimension is required for maintaining peri-implant health is a controversial topic, as various studies have reported opposing results.

The connective tissue fibres around implants run in a direction parallel or oblique to the titanium surfaces and do not attach to the implant. Further, tissue destruction in response to inflammation is more pronounced at implant sites than at teeth. Therefore it is logical that a certain amount of KM is beneficial, stabilising the peri-implant mucosa and increasing its resistance to pathological conditions or attacks.

Indeed, a recent systematic review has concluded that a lack of sufficient KM around dental implants is associated with increased plaque accumulation; tissue inflammation; and mucosal recession; as well as loss of attachment13. The speaker recommended that adequate KM levels at implant sites be ensured from planning to execution.

11 Linkevicius et al. Clin Implant Dent Rel Res 201312 Evans & Chen COIR 200813 Lin et al. J Periodontol 2013

Thoughts on preventing recession around teeth and implantsThere are two types of clinical solutions: osseous and mucosal. Mucosal augmentation can be performed at different stages during the course of treatment. An interesting approach has been suggested which involves soft tissue grafting on the day of implant placement. This method attempts to convert both the morphology and behaviour of thin biotypes to those of thick gingival biotypes14. Another prospective clinical study has reported successful augmentation of labial volumes using GBR and simultaneous implant placement, followed by connective tissue grafting15.

With regard to teeth, several systematic reviews have demonstrated the efficacy of a coronally advanced flap to cover single and multiple gingival recessions. Even more effective was combining the flap with a connective tissue graft16.

Implants generally exhibit more recession than teeth. A prospective cohort study of 10 patients revealed a substantial improvement of tissue levels at implant sites following coronal mucosal displacement in combination with connective tissue grafting. In none of the sites, however, could complete coverage of the implant soft tissue dehiscence be achieved17.

Other studies achieved better results. One study involving 16 patients used tuberosities as donor sites and documented 89.6% mean coverage in single implant recessions, with full coverage among 56.3% of patients18.

Conclusions � periodontal plastic surgery can effectively

prevent biological complications � aesthetic soft tissue problems around implants

are easier to prevent than correct � treatment should focus on the thickness of the

soft tissue � performing a CTG during implant placement

procedures is highly recommended

14 Kan et al. J Oral Maxillofac Surg 2009; Weisner et al. Eur J Oral Implantol 2010

15 Schneider et al. COIR 201116 Cairo et al. J Clin Periodontol 2008; Hofmänner et al,

Quint Int 201217 Burkhardt et al COIR 200818 Roccuzzo et al COIR 2014

“The sooner the recession happens,

the bigger our responsability is“ M. Roccuzzo, SFPIO congress, Lyon, 2016

Tooth malposition Implant in a too buccal position



Bone management for optimal aesthetic outcomesNicolas Picard

Throughout his presentation, the speaker focused on biology, considering tissue morphotype; tooth extraction; healing processes; and subsequent bone resorption. He then outlined two therapeutic concepts: preservation and regeneration.

BiologyTooth extractions in the aesthetic zone are known to be associated with dimensional alterations of the facial bone wall, which can have a profound effect on treatment outcomes. Further, it is recognised that immediate implant placement in a fresh extraction site often fails to prevent bone remodelling in socket walls.

Dimensional changes of the alveolus following tooth extraction were measured in an experimental study. Bone loss was found to occur mainly in the buccal bone plate and measured 2.2 ±0.9mm19. A more recent study investigated the process of socket healing in monkeys. The study observed that levels of bundle bone decreased from 95.5% at 4 days to 7.6% at 180 days along the entire inner alveolar surface20. Another study analysed socket healing using human biopsies. Tissue granulation was reported during the early healing phase and osteoblast levels peaked at 6–8 weeks, remaining almost stable thereafter21.

The width of the buccal bone wall was measured by CBCT. At crestal levels, only 1% of incisors showed thick labial bone (1–2mm); 73% showed a thin bony wall (0.5–1mm); and 25% showed a very thin wall < 0.5mm22.

A 39-patient clinical study used a novel 3D approach for analysing two consecutive CBCTs and found that:

� a facial bone wall thickness of ≤ 1mm was a critical factor influencing the extent of bone resorption

� median bone loss of 7.5mm was registered in thin-wall phenotypes, compared with 1.1mm in thick-wall phenotypes. The results were statistically significant23

The same group of authors created 3D digital surface models by superimposing digital impressions and CBCT data. They measured dimensional changes of the soft tissue after extraction, and found that:

� at the moment of extraction, soft tissue thickness in both thin and thick bone biotypes were similar, averaging 0.7mm and 0.8mm respectively

� in thin bone biotypes, soft tissue thickness increased from 0.7 to 5.5mm after an 8-week healing period

19 Araujo et al. J Clin Periodontol 200520 Scala et al. COIR 201421 Trombelli et al. J Clin Periodontol 200822 El Nahass & Natiem COIR 201523 Chappuis et al. J Dent Res 2013

� in thick bone biotypes, soft tissue thickness remained stable at about 0.8mm

� reduction in vertical tissue levels was similar, measuring 1.6 and 1.4mm respectively24

Ridge preservation vs. immediate implantationTwo recent systematic reviews have concluded that ARP procedures may limit post-extraction resorption, but cannot eliminate it completely. In addition, ARP does not promote bone formation within the socket, and instead the remnants of the graft appear to interfere with the healing process, retarding it. There is only limited evidence supporting the clinical benefits of ARP since implant placement feasibility; success rates; and marginal bone loss are comparable to those in untreated sockets25.

An approach involving immediate implant placement combined with grafting the vestibular gap using DBBM (deproteinised bovine bone mineral) and a collagen membrane has been suggested. This has been shown to reduce bone resorption in an experimental study on dogs, from 2.7 ±0.5mm in control sites to 1 ±0.6mm in test sites26. However, a similar study using the same animal model has found that the technique failed to maintain tissue volumes27.

Vestibular bone dimensions in 14 patients were measured using CBCT seven years after immediate implant placement. It was found that five patients had no buccal bone at all and showed a mean vertical bone loss of 8.7mm. The other nine exhibited a vertical loss of 0.1mm, but the bone was just thick enough to cover the implant surface. Mucosal levels were 1mm more apical in implants with no bone present28.

According to two systematic reviews, in order to prevent mid-facial recession in immediate implant placement29 (Figures 13.2.1–13.2.6):

� patient selection should be based on a thick bone and soft tissue biotype

� the buccal bone wall must be intact � the implant should be placed palatally � immediate placement of a provisional crown is

strongly recommended

Finally, a recent prospective 5-year clinical study evaluated the aesthetic outcome of 22 single immediate implants30. It concluded that: ‘with an aesthetic complication rate of 8/17 in well-selected patients who had been treated by

24 Chappuis et al. J Dent Res 201525 Horváth et al. Clin Oral Invest 2013; Mardas et al.

COIR 201526 Caneva et al. 201227 Favero et al COIR 201528 Benic et al. COIR 201129 Cosyn et al. J Clin Periodontol 2012; Chen & Buser.

IJOMI 201430 Benic et al. COIR 2011


experienced clinicians, type I placement may not be recommended for daily practice’31.

RegenerationA review of the literature32 suggests there is evidence that early implant placement (Type 2) after soft

31 Cosyn et al. J Clin Periodontol 201632 Sanz-Sánchez et al. J Dent Res 2015; Buser et al. J

Periodontol 2013; Chen & Buser IJOMI 2014

tissue healing is associated with a lower incidence of recession when combined with GBR procedures using DBBM (Figures 13.2.7 and 13.2.8).

Ridge augmentation procedures are proven to be effective in treating bone defects prior to or at the same time as implant placement. The speaker concluded that GBR can be considered as the most predictable technique in terms of bone management for aesthetic outcomes.

Figure 13.2.1

Figure 13.2.5

Figure 13.2.2

Figure 13.2.6

Figure 13.2.3

Figure 13.2.7

Figure 13.2.4

Figure 13.2.8


Things we stopped in our practice due to failures

In this session, four different issues were addressed: immediate implant placement; prosthodontic rehabilitation of edentulous jaws; immediate CAD/CAM restorations; and cemented fi xed restorations. These different topics have a common denominator: they are all clinical protocols that have been subject to a change of opinion due to failures.

Immediate implant placementMariano Sanz

Can we infl uence socket healing with immediate implantation? (Figure 14.1.1)There are some biological risks we cannot prevent. A recent histometric comparison between the spontaneous healing of a fresh extraction socket and immediate implant placement in the extraction socket recorded higher vertical bone loss in cases involving immediate implantation, and a tendency towards greater buccal horizontal resorption. The author’s conclusion was that immediate implant placement can jeopardise spontaneous bone remodelling in the socket1.

In clinical scenarios, this biological factor is translated into a substantial reduction in peri-implant tissue volume in immediate implantation. In one study, the horizontal and vertical spaces

1 Discepoli et al. COIR 2014

between the implant and the bone wall were reduced by 63–80% and 65–69% respectively2. Bone resorption levels are lower in posterior teeth and in cases involving thick biotypes, as well as in cases where the implant is placed immediately in palatal and apical positions3 (Figures 14.1.2 and 14.1.3). Although immediate implantation has no infl uence on fi nal implant survival rates, there is an aesthetic risk of marginal buccal recession in about a quarter of patients4.

Are there clinical solutions that can lower the risks of immediate implant?Several clinical approaches have been used to try to counteract this kind of resorption:

2 Sanz et al. COIR 20093 Tomasi et al. COIR 20094 Lang et al. COIR 2010

CAN WE INFLUENCE THE HEALING OF THE SOCKET BY IMMEDIATE

IMPLANTATION?

Publication date: January 2010



Outcome of multilevel analysis

thickness of buccal bone wallthicker betterposition of implantpalatal apical better

Crestal resorption (Horizontal resorption)Crestal resorption (Horizontal resorption)

Apical displacement of the buccal crestApical displacement of the buccal crest


� careful extraction of the hopeless tooth � perfect horizontal and vertical positioning of

the implant � grafting the gap with a slow resorption

biomaterial � increasing the thickness of the soft tissue � performing immediate provisionalisation

Together, these procedures have the capacity to partially reduce hard and soft tissue resorption5.

What are the practical implications?Outside the aesthetic zone, immediate implantation seems to be a reliable method for reducing treatment time: the number of surgical procedures is reduced, and it is a comparatively more comfortable treatment for both patient and dentist. It has been reported that in cases involving upper premolars,

5 Vignoletty & Sanz Periodontology 2000, 2014; Sanz et al. COIR 2016

71% of patients experienced no bone loss, and a small gain was even recorded in the soft tissue margin6 (Figure 14.1.4).

The key decision factors for immediate implantation are:

� socket integrity � thickness of the socket bone wall � patient aesthetic requirements

Immediate implant placement is a technically demanding procedure. The surgeon must avoid placing the implant in a non-optimal vertical or buccolingual position, and must achieve good primary stability. Great care must be taken to assess the socket anatomy, especially in compromised aesthetic areas.

6 Sanz et al. COIR 2013


Prosthodontic rehabilitation of edentulous jawsKarl-Ludwig Ackermann

A complex problem which is often insufficiently plannedThe successful rehabilitation of an edentulous patient depends on various factors, such as residual bone volume and inter-arch relationships. The restoration must meet the functional requirements of the patient, and should:

� be suitable for speaking and chewing � have enough room for tongue function � not entrap food debris � be designed so it can be maintained by the patient

(for example, be easy to clean) � fulfil the patient’s aesthetic expectations

A treatment plan which is based on and tailored to the patient’s individual needs is vital.

Length of clinical experienceThe speaker has 35 years of clinical experience, and illustrated several cases he has encountered which

involved edentulous patients presenting with varying degrees of jaw atrophy. From these cases, he was able to share several conclusions:

� the fit of a framework is key in avoiding technical problems

� passivity is essential to prevent screw loosening � generally speaking, bar retention performs better

than ball attachments (Figure 14.2.1) � milled bars are technically superior to cast bars, as

retention clips need to be changed less frequently � titanium galvano-telescopic restorations

work fairly well, and are the ideal solution for cases involving implants which coexist with periodontal teeth, since occlusal forces are concentrated on the implants rather than on the teeth (Figure 14.2.2)

� zirconia telescopic restorations, however, are not as reliable, as they often suffer fatigue fracture (Figure 14.2.3)

Highly atrophic mandible - ball retained with rubber O-RingsRevision in bar restoration on 4 implants

13.01.2005

05.11.2012

K-L Ackermann

Combination of parodontal and osseointegrated telescopic restorationRevision to a full osseointegrated telescopic design

13.10.2006

22.01.2007

At the time

Today

K-L Ackermann

Moderate atrophied mandible and maxillazirconia telescopic restoration / fatique fracture

22.07.2002 29.07.2003

04.06.2004 At the time

K-L Ackermann

Figure 14.2.1

Figure 14.2.3

Figure 14.2.2


Our first patient in 2003

van Steenberghe et al. 2002 Int J Oral Maxillofac Implants

Scientific evidence of method

8 patients / 9 cases

EAO Paris 2016

Factors influencing deviation between planned and inserted implants (accuracy)

Examination

Double scan-technique:• Production of scan prosthesis• Mucosal fitness and thickness

of scan prosthesis• Ideal tooth set up/alignment• Patient movement during

scanning

Planning & Guide production Insertion of implants

• Planning: Implants lengths and positioning

• Deviation errors may occur in CT scan, Guide production and model creation

The positioning and stabilization of the surgical guide and index:• Fixating pins / mini screws• Mini implants

Vercruyssen et al. 2015

EAO Paris 2016

Clinical and radiographic examination

Radiographic guide

CT/CBCT 3D-reconstruction

Virtual implant positioning in 3D Prefabrication

permanent fixed dental prosthesis

Template guided implant

insertion

Immediate attachment of prefabricated

prosthesis

Clinical and radiographic

follow-up Adjustments of occlusion and

outline

Traditional prosthetic protocol / early function /conventional healing delayed load

Computer assistance in implant dentistry

Things we stopped to do

EAO Paris 2016

Figure 14.3.1

Figure 14.3.3

Figure 14.3.2

Immediate CAD/CAM restoration Margareta Hultin

The beginningsFor two decades, digital techniques in implant dentistry have been evolving, and can now offer high levels of precision. It is now possible to immediately install a full arch fi xed prosthesis made by CAD/CAM, using minimally invasive fl apless guided surgery to optimise implant positioning. The benefi ts for patients are clear: minimal invasiveness; a single surgical intervention; and required treatment time of as little as an hour. In 2002 Professor van Steenberghe and colleagues published their experiences of using this procedure to place fi nal prosthetic reconstructions in eight patients7 (Figure 14.3.1).

Several systematic reviews have evaluated clinical performance of static guided implant placement and immediate loading in edentulous jaws at minimum 1-year follow-up. These reviews concluded that although the number of patients was still limited, survival rates were similar to those of conventional treatment8.

Such great outcomes … so why did we stop?The reviews also reported clinically relevant inaccuracies which led to intraoperative complications, both surgical and prosthetic. The overall rate of complications was found to reach 36.4%, even though the majority of studies involved

7 Van Steenberghe et al. IJOMI 20028 Jung et al. IJOMI 2009; Schneider et al. COIR 2009;

Tahmaseb et al IJOMI 2014; Moraschini et al. Int J Oral Maxillofac Surg 2015

provisional prostheses where the existing dentures were adapted to the inserted implants after surgery.

Factors infl uencing the accuracy of the procedure arise at every step9 (Figure 14.3.2):

� examination: patient movement during scanning; deviations of impressions and models; fabrication and fi t of scan prosthesis

� planning: positioning implants using the software; issues relating to CT scanning; errors in model and guide production

� execution: transferring from planning to the operative fi eld remains the most diffi cult part

Any number of these errors can arise, and cumulatively produce deviations in the maxillary and mandibular arch equally. Fixing the template with pins did not substantially mitigate variations. In some cases, variations in the implant apex positions were signifi cant, and should be taken into account when planning treatment.

So what can we conclude?A comparison of guided and freehand implant placement reveals that the former is superior to so-called ‘mental navigation’10. Guided surgery allows operators to use prefabricated restorations for immediate function, but also comes with risks of complications and deviations, prevents the restorations from being defi nitive (Figure 14.3.3).

9 Vercruyssen et al. COIR 201510 Vercruyssen et al. COIR 2014; Vercruyssen et al. J Clin

Periodontol 2014; Vercruyssen et al. COIR 2015


Cement-retained restorationsKonrad Meyenberg

Facts that make us thinkAfter a period when the majority of implant restorations were screw-retained, cemented retention on simplified abutments became more popular again. Cementation is widely used by prosthodontists because of its simplicity; capacity for hermetic sealing; passive fit; and favourable aesthetic appearance.

However, cement-retained restorations are often associated with mucositis and peri-implantitis, due to open margins and cement excesses (Figure 14.4.1). Cement-retained crowns with a poor marginal fit can cause significantly more crestal bone loss – even in tissue-level implants – than well-fitting crowns after a mean of 3 years11. Increased incidences of inflammation are found in cases where there is an excess of cement around the restoration12. This is especially the case in aesthetic areas, where the abutment finishing line is generally lower and cement excess may be displaced subgingivally, where it is difficult to remove13.

Facts associated with intraoral cementationFact 1. Various techniques have been developed to avoid the excess of cement, such as dual cord application in the sulcus; venting the crown; or using a practice abutment. These techniques have been demonstrated in vitro14, but currently lack definitive conclusions

Fact 2. A high number of cemented restorations exhibit excess cement in the peri-implant sulcus15

Fact 3. Excess cement has been associated with signs of peri-implant disease 81% of cases16

Fact 4. The frequency of undetected excess depends on the type of cement used, and is significantly greater in methacrylate cements than in ZOE cements17

11 Chen et al. Int J Prosthodont 201312 Kosrch et al. Int J Prosthodont 201513 Linkevicius et al. COIR 2011 ; Linkevicius et al.

COIR 201314 Begum et al. IJOMI 201415 Kosrch et al. Int J Prosthodont 201516 Wilson et al. J Periodontol 200917 Korsch et al. Clin Implant Dent Rel Res 2014

Fact 5. Removal of excess cement is difficult. Well-trained clinicians were only successfully able to remove excesses of ZOE cement from models18

Fact 6. The retentiveness of luting agents varies19

Fact 7. The retentiveness of provisional luting agents is less predictable20

Fact 8. The interface between abutment, cement and suprastructure in the subgingival region is a critical area, offering ideal conditions for the formation of biofilms near the crestal alveolar bone. Higher levels of bacteria accumulating on cement lines have been demonstrated in vivo than on machined titanium surfaces21

To conclude: forget cementationA comparison of the clinical performance of screw- and cement-retention reveals no significant differences. However, screw-retained reconstructions exhibit fewer technical and biological complications overall than cement-retained ones22. Technical complications are partially dependent on the systems used.

Fact 9. Occlusal discontinuity of access holes in screw-retained crowns may affect their resistance

Fact 10. Screw retention has the potential for reintervention (Figure 14.4.2)

The speaker recommended that we forget cementation, even though screw-retained reconstructions are more technically complex. For example, a passive fit is crucial for preventing mechanical problems in reconstructions on multiple abutments, and it is advisable to convert conical connections to flat non-locking ones in order to facilitate passivity (Figure 14.4.3).

18 Behr et al. IJOMI 201419 Garg et al. J Oral Implantol 201420 Schiessl et al. Clin Oral Investig 201321 Papavasileiou et al. Int J Prosthod 201522 Wittneben et al. Clin Implant Dent Rel Res 2013;

Wittneben et al. IJOMI 2014


Figure 14.4.1

Figure 14.4.2

Figure 14.4.3


Debate: ‘machined or rough implants?’This session explored whether the advantages of rough implants outweigh the increased risk of biological complications.

Machined vs. rough implants: 30 years of experienceMassimo Simion

Historical visionThe ‘golden age’ of osseointegration lasted from 1980, when machined implants were first used extensively, until around 2000. From then onwards, modified surfaces were introduced to the market, and at almost exactly the same time, a tsunami of peri-implantitis hit. The Estepona Consensus defines peri-implantitis as an infection involving suppuration and progressive bone loss1.

Studies from the ‘golden age’A recent 20-year follow-up study documented survival rates for machined implants of 99.2%, with mean marginal bone loss around implant sites of less than 2mm and a prevalence of biological complications of 2.4%2. Another clinical study showed a cumulative survival rate (CSR) of 93.35%; mean marginal bone loss of 0.78mm; and no incidences of peri-implantitis after 12 years of follow-up3. A retrospective study of machined implants in native bone – with a mean

1 Albrektsson et al. Clin Implant Dent Rel Res 20122 Astrand et al. Clin Implant Dent Rel Res 20083 Simion et al. Clin Implant Dent Rel Res 2014

follow-up period of 15 years – recorded a CSR of 96.8%, with peri-implantitis in 1.3% of cases. The behaviour of machined implants in augmented bone differs slightly: another recent retrospective study documented a similar CSR at 13–23 years of follow-up, but an incidence rate of peri-implantitis of 9.9%4.

Studies in the middle of the tsunamiWith regard to vertical augmentation, a retrospective study of 88 patients and 246 implants with 15 years follow-up revealed rapidly progressing bone loss in 28.5% of 105 implants.5

Close-up images of implant surfaces provided by a scanning electron microscope (SEM) may explain the difference in these results. A hypothesis could be that rough implant surfaces are more susceptible to microbiota, with microscopic pathogens adhering to the surface, leading to resorption and higher levels of marginal bone loss around the implant.

4 Simion et al. Int J Period Rest Dent 20165 Simion et al. in progress


Clinical advantages of modern micro-rough implant surfacesDaniel Buser

An alternative historical visionIt may be that the ‘golden age’ of osseointegration was not so golden. In the 1990s, patient morbidity was improved when the use of modified surfaces with high osteophytic potential became widely used:

� shorter implants reduced the need for procedures like sinus floor elevation and vertical ridge augmentation, and bicortical stabilisation became obsolete

� early failures were reduced through submerged or non-submerged healing

� healing periods and overall treatment times became shorter, with immediate and early loading between 4–8 weeks

� equal success rates were achieved in the maxilla and mandible, even in areas with low density bone

After a development phase that lasted about two decades, there was a paradigm shift towards micro-rough surfaces in the late 1990s. Implant surfaces with a roughness measuring between 1–2μm achieved higher bone-implant contact levels and better removal torque values in experimental settings. This was soon translated into clinical data.

The most recent advance has been the shift in focus from topography to chemistry. After in vitro and in vivo preclinical studies6, the introduction of the SLActive surface has further shortened healing times to as little as three weeks7.

Clinical long-term documentation of micro-rough surfacesThe late failure rates recorded at 10 years make up less than 5% of the cases reviewed by Albrektsson and colleagues in 20138. The speaker himself has published a retrospective study of 511 implants in 303 patients, recording a survival rate of 98.8% and success rate of 97% at 10 years. These figures clearly differ from those documented in a recent study of the patient cohort treated from 1986–88 with titanium-plasma sprayed (TPS) implants, where the success rate is 75.8% at 20 years9.

6 Buser et al. J Dent Res 2004; Schwarz et al COIR 2007; Schwarz et al. J Clin Periodontol 2008

7 Borstein et al. Clin Implant Dent Rel Res 2009; Borstein et al J Periodontol 2010

8 Albrektsson et al. Clin Implant Dent Rel Res 20139 Buser et al. Clin Implant Dent Rel Res 2012 and

Chappuis et al. Clin Implant Dent Rel Res 2013, respectively

‘Why has there been such good long-term success at the University of Bern?’ the speaker asked. He said that it is because of several factors:

� all the studies featured tissue-level implants � all studies followed strict surgical principles with

circumferential bone anchorage � each patient entered a supportive care

programme

Poor treatment quality leads to a higher risk of peri-implantitisAlthough the topic is controversial and the exact definition of peri-implantitis is disputed, the main causes of peri-implantitis seem to be:

� poor surgical technique (such as lack of buccal bone wall; poor positioning of the implant; or overly aggressive technique)

� poor prosthetic procedures (excessive use of cement; use of prostheses which are difficult to clean; or poorly fitting components)

� lack of patient maintenance programmes

The shape and surface of the implant, including manufacturing quality, could also be considered a potential risk factor for peri-implantitis.

The typical outcome: rough area exposed to oral environmentIf, after initial resorption, the rough implant surface is supracrestal, its porosity is more susceptible to oral biofilms.

Bone response to implant placement depends on several factors. In cases involving poorly positioned implants, initial bone resorption will be greater. In procedures involving vertical bone augmentation it is difficult to reach the bone level originally predicted exactly, and a few millimetres of rough surface usually remain supracrestally. It is also recognised that the position of the implant’s micro-gap and its characteristics influence the response and stability of peri-implant tissues10. There are several arguments for using a hybrid (machined/rough) surface design or tissue-level implants.

The speaker concluded that the main influencing factor is treatment quality. Widespread placement of implants by unqualified or inexperienced individuals is a problem that must be addressed by all players: governments, universities, associations, med-tech companies, and so on.

10 Broggini et al. J Dent Res 2006


Please give me back my smile! Decision-making in the aesthetic zone: challenge your speakersHow to manage complex cases in the anterior maxilla using a multidisciplinary approachTeam 1: Markus Hürzeler and Otto Zuhr

A good aesthetic result is an essential measurement of success when placing implants in anterior regions. However, achieving a result that is both aesthetically and functionally optimal in the maxillary anterior area is not straightforward. Tooth extraction in this area is widely associated with volume reduction, and it is often necessary to compensate for this reduction before implants can be placed.

When conditions are less than ideal, it can be especially challenging to place an implant where a single tooth is missing or needs to be extracted. In these unfavourable cases the evidence-base underpinning available treatment options is often limited. Although predictability is a key issue and evidence is often limited, the speakers conceded that sometimes careful and judicious use of less proven techniques may be considered, provided that the duration of their outcomes can be expected to last for at least 5–10 years.

The speakers presented some complex cases involving seemingly hopeless teeth which exhibited

fractured posts and appeared extremely difficult to rebuild. The approaches they described might typically be considered as temporary, but their main objective was to delay implant placement and keep the tooth in the mouth for as long as possible.

In compromised cases, it is particularly important that the decision-making process takes the patient’s perspective into account. Currently there is a trend towards using patient reported outcome measures (PROMs) as a way of evaluating the success of treatment. Patients typically prefer fewer surgical procedures; less invasive treatment; and options that minimise postoperative pain. When planning treatment, an evidence-based approach which also takes these factors into account must be made. As a result, the speakers generally prefer microsurgical techniques as they are both minimally invasive and have the potential to offer improved results.

An interdisciplinary approach is usually the best solution, and as an example the speakers presented a case which used orthodontic extrusion to gain

Figure 16.1.1


vertical bone. This protocol usually requires 6 to 12 months for tooth movement followed by a retention period lasting 6 months.

The next case they described featured staged treatment involving:

� extraction followed by a waiting period of 6 months to allow initial socket remodelling

� bone block augmentation, with double collagen membranes used to cover the block

� a 6–8 month healing period � implant placement � a ‘buttonhole’ incision made at the muco-gingival

junction to passively advance the flap without reducing the depth of the vestibule

The speakers then described their novel ‘socket-shield’ technique. Currently, a follow-up of five

years is available for a small number of cases, and initial results are promising. However, the speakers stressed that further scientific evidence to support the technique is required.

Conclusions � every case in the aesthetic area must be

considered difficult, especially if patient expectations are high

� the protocol for treating cases in the aesthetic zone depends on individual patients’ perspectives

� an interdisciplinary approach often provides the best solution. This may involve orthodontic treatment or a staged augmentation procedure

� it is generally advisable to keep the tooth in the mouth for as long as possible



Contemporary management of complex aesthetic dilemmas with an interdisciplinary approachTeam 2: Tidu Mankoo and Laura Frost

The second presentation outlined how to treat cases in the aesthetic zone using an interdisciplinary approach. The speakers discussed the use of regenerative periodontal treatment combined with orthodontics and implants. In cases involving compromised dentition, three challenges are frequently found:

� compromised structure � compromised soft tissue aesthetics � compromised periodontal environment

An interdisciplinary treatment plan can help overcome these obstacles.

Biology, form, function, aesthetics and precision must be addressed in complex cases. The speakers presented five clinical cases which they resolved taking these elements into account. Drawing on extensive clinical experience, they based their treatment plans on four aspects: dental, periodontal, occlusion and aesthetics.

Case 1This case was treated in five stages:

� control phase: this was necessary to prevent periodontal inflammation; repair carious lesions; and perform endodontic treatment

� corrective phase: consisting of provisionals; orthodontics; surgical periodontics; bone and soft tissue correction; and implant placement

� re-evaluation: during which final adjustments are made to the provisionals in order to stabilise the positions of the teeth and the occlusion is fitted

� definitive restoration: during which a further evaluation is carried out

� maintenance

An 18-year follow-up has revealed good results (Figure 16.2.1). Factors influencing long-term outcomes are:

� bone � soft tissue � components (including implants, abutments

and prosthetics as well as design, shape, surface and connection)

Case 2The second case required hard tissue augmentation before the orthodontic treatment phase. After that, a soft tissue graft was performed, and then the implant and the provisionals were placed (Figure 16.2.2).

Case 3The third case involved multiple recessions and required orthodontic intrusion as a first stage in resolving the aesthetic problems. All but one tooth was preserved. A single implant was placed and a soft tissue graft was carried out before the final rehabilitation (Figure 16.2.3).

Case 4The patient in case 4 presented with severe periodontitis. An initial stabilisation phase was followed by orthodontic extrusion of the hopeless teeth. These were then extracted, and the extraction sites prepared for immediate implantation. A surgical and prosthetic protocol to preserve bone volume and thickness of the labial soft tissue was followed. The restoration was constructed on small bridges which were designed to facilitate maintenance (Figure 16.2.4).

Figure 16.2.1

Figure 16.2.2


Thoughts on immediate implants:

� wherever possible, a flapless technique is recommended. If a flap is necessary, bone substitute grafts should be used

� place the implant towards the palate and avoid wide platform implants

� anorganic bone bovine mineral (or similar) should be used in the gap between the implant and buccal wall of the socket

� a connective tissue graft should be performed to thicken the tissue

Case 5The final case also involved orthodontic extrusion (which may usually last 3–6 months, then is retained for 3 months). The final restoration made use of the single and small bridges concept (Figure 16.2.5).

An approach using orthodontic extrusion has substantial benefits when compared with conventional treatments which are based on surgical reconstruction or hybrid prostheses:

� surgery is less invasive � prostheses can be more easily designed

and fabricated � it offers biological and biomechanical

advantages � it can provide improved stability � it facilitates good oral hygiene and

ongoing maintenance � the phonetics are likely to be better

But it also has limits:

� clinical attachment is needed � teeth must be viable � infection must be eradicated, or at least

controlled well � orthodontic anchorage is required � the appearance of interdental papillae will not

be perfect but ‘good’ at best � the patient must still have teeth in the

affected areas

The speakers concluded that the therapeutic approach they presented during the EAO conference in Barcelona nine years ago continues to be valid (Figure 16.2.6).

Figure 16.2.3

Figure 16.2.4

Figure 16.2.5

Figure 16.2.6

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